Beginner Macro: Increasing working distance from subject and less cropping...

[Forkbeard]

I have been using my LX100 with a Raynox 250 for macro shots and am fairly happy with the results, but the working distance is quite short (about 4 inches) for photographing flighty insects etc. I'm also using the Lumix EZ function at 3.15mp (essentially a centre crop, enabling you to increase focal length) at 150mm from the 'native' 75mm/12mp at the long end. How can I get a longer working distance and fill more of the frame, leaving me with a larger image and not having to crop as much? I've read some of the threads in here but have ended up tying myself in knots with all the different options! I realise this will have to involve buying a different camera/lens combo of some sort. There are a few functions I would like to keep if possible such as the focus peaking.

Also, is it possible to use to Raynoxs together somehow? Or would that be unworkable (making working distance even shorter on my current setup for example)?

Here is what I'm getting so far:

P1000459

Garden Cross Spider (Araneus diadematus)

 

[Kodiak Qc]

(essentially a centre crop, enabling you to increase focal length)

Sorry man but it doesn't! This is a misunderstanding.
The only thing that will change is the AoV, nothing else.
Cropping the capture will never affect the characteristics
or properties of any lens.

When I want greater distance from the subject, I use my
dedicated 200 mm macro lens and mounted on a higher
pixel count sensor and that does wonders.

 

[Forkbeard]

Sorry man but it doesn't! This is a misunderstanding.
The only thing that will change is the AoV, nothing else.
Cropping the capture will never affect the characteristics
or properties of any lens.

When I want greater distance from the subject, I use my
dedicated 200 mm macro lens and mounted on a higher
pixel count sensor and that does wonders.

Sorry, I should have phrased that better: I should've said 'It gives you the appearance' of increasing focal length. I know it doesn't actually increase focal length, but giving that appearance when shooting (vs cropping afterwards) helps with framing the shot, focusing etc.

 

[Kodiak Qc]

I should have phrased that better

Maybe it is I who misread you! :banghead:

 

[Forkbeard]

Maybe it is I who misread you! :banghead:

Nope, my bad. I definitely said it

You mentioned the 200mm; My thinking is get something along the lines of an fz1000, giving me greater choice/length focal wise and gives me a bump up in megapixels. I'm not sure I want a dedicated macro lens as it would be an expensive purchase and would probably only do that one job. Maybe a dslr and telephoto zoom would better. But would I lose depth of field on the bigger sensor (although I'm limited to f16 with the lx100 anyway)? I've been looking into focus stacking but I don't think it's for me - I would prefer to avoid tripod and carrying more kit.

 

[Kodiak Qc]

something along the lines of an fz1000

What is that?

would I lose depth of field on the bigger sensor

DoF is a characteristic that is lens dependent,
nothing to do with the crop.

I've been looking into focus stacking

I really to work with focus stacking in studio but
in the wild ~.

Explore longer focal length with maybe extension tubes?

 

[Forkbeard]

What is that?

DoF is a characteristic that is lens dependent,
nothing to do with the crop.

I really to work with focus stacking in studio but
in the wild ~.

Explore longer focal length with maybe extension tubes?

The fz1000 is a high end superzoom bridge camera (which I've talked myself out of anyway). I thought smaller sensors have naturally more depth of field at whatever aperture you use. I decided to go down the DSLR route and (re)bought a 600D along with a Tamron 70 300 VC. I sold one previously to buy something smaller, but now I have both! I guess you live and learn.

This setup with my Raynox adaptor should give me that extra working distance and a bit more magnification at say, 200/250mm? Not to mention I won't have to shoot at 3mp

 

[Phil V]

...
DoF is a characteristic that is lens dependent,
nothing to do with the crop.

...

Sorry but depth of field has a very strong relationship to sensor / film size.

It's almost impossible to create an OoF background at normal distances on a phone cam, and creating any kind of depth of focus on a 10x8 requires stratospheric f no's.

 

[Kodiak Qc]

Raynox adaptor

Never used it so I wouldn't know!

 

[Graham]

I guess this is a bridge camera?
There is one man on here that I know is good with bridge cameras and 2 raynox coupled together, its @GardenersHelper , This man does stunning macro.

 

[myotis]

This setup with my Raynox adaptor should give me that extra working distance and a bit more magnification at say, 200/250mm? Not to mention I won't have to shoot at 3mp

The working distance with a close up lens is determined by the close up lens. They work by reducing the focal length of your camera lens so that when you set your camera lens at infinity, it will actually be focussed at a distance determined by the power of the close up lens. When you change the focal length of your camera lens, you alter the magnification, but not the working distance.

So a +1 c/u lens focuses at 1m if your camera lens is set at infinity, a +2 c/u lens focusses at 500mm, a +3, 333mm, a +4, 250mm,. The working distance will change slightly as you focus, but only to decrease the working distance. I have assumed the raynox "250" is a +4 close up lens.

In practice, with modern complex camera lens designs and zoom lenses, these distances are unlikely to be correct, but if you want to increase your working distance, the only way to do this is, as Kodiak suggested, is to use a longer dedicated macro lens, or a longer lens with extension tubes or focusing bellows.

Or learn to work with the short working distances, which lots of people do. For some people, a working distance of 4 inches would be a luxury.

But there a many ways of approaching this, but you aren't going to solve your working distance problem by changing camera/lens while still using the Raynox 250, but you should be able to increase the magnification by attaching the Raynox to a longer lens.

 

[Kiwi Paul]

If you use extension tubes you can increase the magnification by allowing the lens to move closer to the subject. Here are 3 examples of my 70-300 lens @ 300mm with minimum focus distance with no tubes, a 16mm tube then an additional 10mm tube (total 26mm).

No tube


16mm tube


16 + 10mm tubes (26mm)


But a dedicated macro lens allows much closer focus here is my 90mm macro lens with no tubes, not the best of shots but demonstrative only.

 

[GardenersHelper]

The Raynox 250 is a +8 diopter close-up lens, so when the camera lens is focused at infinity the working distance is around 1000mm / 8 = 125mm. This is the maximum working distance. The working distance decreases as you focus closer.

The Raynox 150 is a +4.8 diopter close-up lens with a maximum working distance of around 1000mm / 4.8 = 208mm. The Canon 500D is a +2 diopter close-up lens with a maximum working distance of around 1000mm / 2 = 500mm.

You can "stack" close-up lenses. You add the diopter value of each to get the diopter value of the combination. I have used a Raynox 150 and Raynox 250 stacked (+12.8 diopters), a Raynox 250 and Raynox 250 stacked (+16 diopters)

I have also used a Raynox MSN-202 (+25 diopters) and a Raynox MSN-505 (+32 diopters). The working distance gets progressively shorter as the diopter value increases. For example, the MSN-505 has a maximum working distance of around 1000mm / 32 =31mm.

I have used all of these on bridge cameras with small, 1/2.3" sensors (Canon S3 and SX10, Panasonic FZ200 and now FZ330), on micro four thirds cameras (Panasonic G3, G5 and now G80) and on a Canon APS-C camera (70D).

The FZ330 has a 25-600mm equivalent lens. On the G80 I use a 45-175 lens (90-350mm equivalent). On the 70D I use a 55-250 lens (88-400 equivalent).

As mentioned above, it is the power of the close-up lens that determines the maximum working distance not the kit that you are using it on. The camera/lens does determine the minimum working distance. For example the minimum working distance when using a macro lens will be less than the minimum working distance when using a non-macro lens.

The maximum Depth of Field you can get with a close-up lens depends on the minimum aperture available on the camera lens. It also depends on the sensor size.

For example, the minimum aperture on my bridge cameras is f/8. This gives a depth of field equivalent to f/45 on a full frame camera.
The minimum aperture on the 45-175 that I use on my micro four thirds cameras is f/22. This gives a depth of field equivalent to f/45 on a full frame camera.
The minimum aperture on the 55-250 that I use on my APS-C camera varies from f/22 to f/32 depending on focal length. At around f/28 this gives a depth of field equivalent to f/45 on a full frame camera.

Therefore, although cameras with smaller sensors give greater depth of field for a given aperture, because they can't use such small apertures as larger sensor cameras the maximum depth of field turns out (with the lenses I use) to be roughly the same for all three sensor sizes that I use.

The FZ1000 (which I don't use) is an exception to this, and so is the FZ2500. In order to get f/45 full frame equivalent depth of field like the other setups above the FZ1000 would need an aperture of f/16. However, its minimum aperture is f/8. Since depth of field roughly halves for every two stops increase in aperture the FZ1000 can only give around 1/2 of the depth of field of most setups. The FZ2500 has a minimum aperture of f/11 and its maximum depth of field is around 40% smaller than most setups.

A lot of people (most people in my experience) won't use very small apertures like the minimum apertures quoted here because of the very significant loss of sharpness/detail that you get when using very small apertures. However, there is a trade-off with depth of field and there is a small number of people (I am one of them) who prefer to live with the loss of sharpness/detail in order to obtain the greater depth of field.

This is only the case for single shots. For stacking using multiple shots it makes great sense to use the camera's optimum ("sweet spot") aperture for sharpness/detail. Stacking has its own trade-offs compared to single shots: it is no good for subjects that are moving around (or being moved around in a breeze) or are only present or still for a short period; capturing the images for a stack and processing them takes significantly longer than capturing and processing single images.

The above calculations relate to the use of close-up lenses. The calculations, and the obtainable depth of field, are different if using a macro lens, extension tubes, teleconverters, bellows and/or reversed lenses.

One of the reasons I use close-up lenses (a big reason for me) is that I can use autofocus down to scenes 5mm across or smaller. Most people don't use autofocus for close-up/macro work. I have found autofocus unusable when using macro lenses and/or extension tubes etc. In some cases this is because it is too slow, with the lens "hunting" for a long time, sometimes because the autofocus simply won't find focus, and there are some lenses, especially the more powerful ones (for example a Venus optics macro lens up to 2:1 and a Canon macro lens that goes to 5:1 magnification) which are manual focus only.

 

[woof woof]

DoF is a characteristic that is lens dependent,
nothing to do with the crop.

Sorry but depth of field has a very strong relationship to sensor / film size.

It's almost impossible to create an OoF background at normal distances on a phone cam, and creating any kind of depth of focus on a 10x8 requires stratospheric f no's.

A tiny sensor device like a phone or compact will not have a 100mm f2.8 macro lens, it'll have a 5mm something or other. Put the 100mm f2.8 on both and stand in the same spot and take two pictures and the smaller sensor device will give you... drum roll...

a. Less DoF.
b. More DoF.



I know which my money is on and why

 

[woof woof]

One thing to think about could be an older MFT camera like the Panasonic G1. I had one of these for years and liked it very much and these days they start at £50 or so. You can use old manual focus film era lenses on these cameras via a £10 adapter bought off evil bay. 50, 80 or 100mm macro lenses crop up quite often and as these cameras are x2 crop that'll give an equivalent of 100, 160 or 200mm and the Raynox could be added. I have a 50mm f2.8 macro which cost about £60, I've seem 50mm macros go for £40 and up and 80 and 100mm macros going for anything between £80-150 depending on focal length and make.

A G1+adapter+lens could be had for a little over £100 or so with careful shopping. At ISO 100-400 I think that the G1 is excellent and I'd happily crop to 100%.

Worth thinking about?

 

[Carlh]

Use a longer lens (telephoto, 200mm) either with your raynox or with a one of the tubes from a set of extension tubes (but only one from the set, might take some getting used to figuring out which one is best to use). I shot (very badly I might add) rain drops on leaves from about 10 feet away but because of the distance, wobble (natural blood flow) caused the lens to shift every so tiny, but over 10 feet, that meant a few cm's to more than an inch so did not work out too well - btw I imagine if you can get within 5 feet, then you may get lucky with some burst shots and very steady hand and even better, no pulse (serious, though dont go topping yourself, you'll need to still be alive when taking the image)

 

[myotis]

A tiny sensor device like a phone or compact will not have a 100mm f2.8 macro lens, it'll have a 5mm something or other. Put the 100mm f2.8 on both and stand in the same spot and take two pictures and the smaller sensor device will give you... drum roll...

a. Less DoF.
b. More DoF.



I know which my money is on and why

I'll bite, as depth of field is dependant on aperture and and magnification (not sensor size or focal length) assuming the lens is at f2.8 for both pictures, depth of field will be identical.

Of course that situation is unlikely to occur, as normally you want to keep the angle of the view the same (to get everything in), so you will have a smaller magnification (using a shorter lens, or standing further back) on the phone, and hence get more depth of field by virtue of the smaller image size.

 

[woof woof]

I'll bite, as depth of field is dependant on aperture and and magnification (not sensor size or focal length) assuming the lens is at f2.8 for both pictures, depth of field will be identical.

Of course that situation is unlikely to occur, as normally you want to keep the angle of the view the same (to get everything in), so you will have a smaller magnification (using a shorter lens, or standing further back) on the phone, and hence get more depth of field by virtue of the smaller image size.

Really we should avoid all talk of equivalence as it causes so much grief especially when someone mentions the circle of confusion but in this case with the pictures taken from the same position (as we're shooting macro) I'd say that the smaller sensor would look like it has the least DoF as the subject, or what you could see of it as the lens would have a much greater crop factor applied, would be much bigger in the frame and therefore IMO there'd be next to no DoF if the images were about the same size but of course you could get next to no DoF with the larger sensor too by performing a heavy crop to match that of the small sensor and keeping about the same sizes. As you said, it's not going to happen in the real world and as you also say magnification is one of the key things. Anyway, I don't think that sensor size as such affects the DoF but effectively it does as it may well lead to the use different lenses or to change position if we're using the same lens

 

[myotis]

Anyway, I don't think that sensor size as such affects the DoF but effectively it does as it may well lead to the use different lenses or to change position if we're using the same lens

I agree with confusion of equivalence, and that's why its useful to think in terms of just aperture and magnification, rather than focal lengths and sensor sizes.

To use another example, pertinent to this tread, if you are using full frame, and photographing something at 1: 1, and you take three photographs, one wth a 50mm, lens, one with a 100mm lens and a third with a 200mm lens, all at f11, you will change the working distance, but the depth of field stays the same. So if you need more depth of field, you need to reduce the image size, or stop the lens down more.

 

[GardenersHelper]

A tiny sensor device like a phone or compact will not have a 100mm f2.8 macro lens, it'll have a 5mm something or other. Put the 100mm f2.8 on both and stand in the same spot and take two pictures and the smaller sensor device will give you... drum roll...

a. Less DoF.
b. More DoF.



I know which my money is on and why

I'll assume they are using the same aperture, say f/8, and that the subject is 5m away. The DoF for a small sensor camera with a 1/2.3" sensor will be around 0.22m. the DoF for a 1.6x crop factor camera will be around 0.79m.


02 small sensor dof by gardenersassistant, on Flickr


01 1.6x dof by gardenersassistant, on Flickr

Calculated using the Depth of Field calculator on this page at Cambridge in Colour.

However, the angle of view will be different. By my calculations (using the formula found here of AOV = 2 * arctan( d / 2f) radians and converted degrees) the horizontal angle of view in landscape orientation for the small sensor camera will be around 3.5 degrees and for the 1.6x crop factor camera will be around 13 degrees.

I use cameras with different sensor sizes and want to match DoF sometimes. I find it simplest to use a rule of thumb based on equivalent apertures. For example, for a given angle of view I get the same depth of field with my 1/2.3" sensor cameras at f/8, my micro four thirds cameras at f/22 and my APS-C camera at f/28. This difference of around 3 stops between small sensor and MFT and 2/3 stop between MFT and APS-C is what I use when translating aperture settings between cameras for a particular DoF use case.

This method works with bare lenses at non-macro scale and at macro scale when working with close-up lenses. The calculations are more complicated at macro scale with macro lenses, extension tubes and teleconverters because of the impact of magnification on effective aperture. Fortunately (for me) I never use macro lenses etc in circumstances where I would want to calculate a DoF-equivalent aperture.

 

[myotis]

I'll assume they are using the same aperture, say f/8, and that the subject is 5m away. The DoF for a small sensor camera with a 1/2.3" sensor will be around 0.22m. the DoF for a 1.6x crop factor camera will be around 0.79m.

So according to this, at the same image size, the larger sensored camera is giving three times more depth of field than the smaller sensored camera. I assume this is because both are being enlarged different amounts to get to that 10" print size that they use here by default.

This doesn't match my tests, or my understanding of the calculations, but I did do them 40 years ago, so maybe I mis-remember. I obviously need to revisit this.

 

[Forkbeard]

Thanks for all the replies, it's cleared things up quite a bit (and confused the crap out of me ). I won't even try to reply to everyone individually, but I am still watching/reading the thread.

 

[GardenersHelper]

So according to this, at the same image size, the larger sensored camera is giving three times more depth of field than the smaller sensored camera. I assume this is because both are being enlarged different amounts to get to that 10" print size that they use here by default.

This doesn't match my tests, or my understanding of the calculations, but I did do them 40 years ago, so maybe I mis-remember. I obviously need to revisit this.

I find it more useful (for my purposes) to consider the situation when the angle of view is the same for two different sensor sizes (I want to match the DoF for a particular scene).

For example, let's consider a 60mm lens on micro four thirds (MFT) versus a bridge camera with a 1/2.3" sensor.

The MFT with 60mm lens has an angle of view of around 16 degrees. To get the same angle of view with the bridge camera needs a focal length of around 21.5mm. At these focal lengths, and with both cameras set to f/8, the DoF at 1 metre from the centre of focus will be around 19cm for the small sensor camera and around 7 cm for the MFT camera.


03 small sensor DoF same angle of view and aperture as MFT by gardenersassistant, on Flickr



04 MFT DoF same angle of view and aperture as small sensor by gardenersassistant, on Flickr

To get the same DoF as the small sensor camera gets at f/8 you need to use a smaller aperture, f/22, on the MFT camera.


05 MFT DoF same angle of view as small sensor, DoF-equivalent aperture by gardenersassistant, on Flickr

 

[myotis]

I find it more useful (for my purposes) to consider the situation when the angle of view is the same for two different sensor sizes (I want to match the DoF for a particular scene).

I'm happy with this as I think in terms of image size and this this example when you reduce the image size (with a shorter lens) you get more D of F, and if you keep the image size the same and stop down you increase the D of F. This is what I would expect. When I did this sort of thing, every print I produced needed to have the magnification identified so I am just in the habit of thinking in terms of image size rather than angle of view

I still don't follow the earlier example where the the same size image on the larger sensor is give three times the depth of field.

 

[GardenersHelper]

I still don't follow the earlier example where the the same size image on the larger sensor is give three times the depth of field.

Isn't this because the two images are not of the same scene? (The larger sensor is covering a much wider angle of view).

 

[myotis]

Thanks for all the replies, it's cleared things up quite a bit (and confused the crap out of me ). I won't even try to reply to everyone individually, but I am still watching/reading the thread.

It is confusing, partly because there are lots of options of doing the same thing, and what you do depends on the quality you demand and the subject matter. As you photograph smaller and smaller things, the difficulties increase exponentially, especially if they move.

The poll is really impossible to answer, as the right answer depends on too many things. My personal main starting point for general close up work has always been (on full frame) a 105mm dedicated macro lens. It gives reasonable working distances, and is easy to use, especially as now a days, most will focus from infinity to 1:1 magnification. But I also had 55, and 200 micro-nikkors available.

Another option is a tele-zoom I used an 80-200 on full frame, with lower power close up lenses than your raynox (+2 and +3). This is useful because although you are stuck with a fixed working distance, you can change the magnification by zooming the lens.

You can still add the raynox to either the 100 or zoom to increase magnification. Assuming you are interested in general photography as well as close up stuff, the Tamron zoom with a couple of lower power close up lenses is probably the most versatile, even if it isn't necessarily capable of the highest quality.

Once you get into this you will end up with all sorts of bits and pieces and lenses, and develop your own working practices, but the above is where I would probably start.

 

[myotis]

Isn't this because the two images are not of the same scene? (The larger sensor is covering a much wider angle of view).

I don't think It should make a difference. If you imagine a 5' x 4" sensor, with a 100mm lens at f8. There is a row of fence posts running away from you down the centre of the picture you have just taken, and you have focussed on one of the fenceposts.

If you crop the view so it matches what you would seen with a 24mm x 36mm sensor with the same lens, but includes the line of fenceposts, is there any reason to think it should have more or fewer of the fenceposts in focus than when you looked at the image from the full 5x4 sensor.

 

[Forkbeard]

So basically, if I stick with the raynox my working distance is the same, but I can increase focal length and get more magnification? I can live with that.

So I'm going with a 55 -250 Canon STM IS. I can increase focal length/magnification and no longer have to shoot at 3.15mp to get the 150mm equivelant with the EZ function on the lx100. So I can shoot at full resolution and then crop which is a bonus.


I deleted the poll.

 

[myotis]

So basically, if I stick with the raynox my working distance is the same, but I can increase focal length and get more magnification? I can live with that.

So I'm going with a 55 -250 Canon STM IS. I can increase focal length/magnification and no longer have to shoot at 3.15mp to get the 150mm equivelant with the EZ function on the lx100. So I can shoot at full resolution and then crop which is a bonus.
.

Yes, except zooms are funny beasts and they don't all behave the same way with close up lenses.

I have just looked and with my Nikon 18 - 200 zoom with a Canon 500d close up lens (much less powerful than your Raynox) on an APS Nikon. I can zoom from a subject size of about 10" long to one of 2.5" long filling the frame, while keeping approximately the same distance from the subject. But it needs more refocussing, and slight adjustments to the working distance than I would have hoped for.

 

[GardenersHelper]

So basically, if I stick with the raynox my working distance is the same, but I can increase focal length and get more magnification?

Yes. But bear in mind that with a camera lens that extends as you zoom, like the 55-250 STM, as you change the focal length/magnification/framing you may need to move the camera to get the working distance back into the zone where you can gain focus. This becomes more of an issue with more powerful close-up lenses.

So I'm going with a 55 -250 Canon STM IS.

Remember also that you can only get a particular range of magnifications/scene widths with a particular close-up lens on a particular piece of kit. For example, with the Raynox 250 on my 55-250 STM on my 70D I can capture scene ranging from around 50 mm wide at 55mm focal length down to around 12mm wide at 250mm.

What scene sizes you need to cover depends on what size of subject you are interested in and, for insects and spiders for example, whether you want to capture full body shots, parts of the body or the creature in its environment. If you want to do all of these and/or photograph subjects of very different sizes you may need more than one close-up lens. For example, when I used my 70D as my primary flower camera I would generally use the 55-250 by itself or with a mild Canon 500D close-up lens. For insects etc I most often use a Raynox 150, which is between the Canon 500D and the Raynox 250 in power (and working distance). However, I tend to go for whole body and environmental shots not "flies' eyes".

If you have a Raynox 150 and 250 you can stack them, which cover scene widths from about 32mm down to about 8mm on my 70D with 55-250 STM. The Raynox 150 by itself on the 55-250 covers scene widths from about 85mm down to about 19mm.

I can increase focal length/magnification and no longer have to shoot at 3.15mp to get the 150mm equivelant with the EZ function on the lx100. So I can shoot at full resolution and then crop which is a bonus.

Yes. What camera are you going to mount the 55-250 on?

I have the 55-250 STM on a 70D. It works ok but ... I don't know if you'll want to use autofocus. I use live view almost all the time for close-up/macro and the autofocus with Raynox lenses on the 55-250 works, but is not brilliant. I use a single focus box so I can place the centre of focus where I want, but the smallest focus box on the 70D is rather large compared to my Panasonic cameras, which makes for less precise focusing. Also, the focusing is significantly slower than with my Panasonic cameras and sometimes won't find focus at all in circumstances when the Panasonics will. You might want to take a look at this post in the Macro and Close-up forum. (Incidentally, you may get better feedback about/help with macro/close-up issues by posting in the Macro and Close-up forum. There is a wide range of experience there, including beginners, so you don't need to be shy about joining in and asking questions/seeking feedback.)

 

[GardenersHelper]

Yes, except zooms are funny beasts and they don't all behave the same way with close up lenses.

Very true. I initially had a 55-250 IS II and autofocus was poor with a weak close-up lens and wouldn't work at all with the Raynox 250 and more powerful close-up lenses. Autofocus works (with limitations, see previous post) with the Raynox 250 and stronger with my 55-250 IS STM.

 

[Forkbeard]

I'll be using the 55 -250 on a 600d body and my main interst is insects/bugs etc and possibly some food photogrpahy (which won't be too extreme anyway). I don't use autofocus at the moment and didn't plan on using it when I use the Canon, but I currently have focus peeking which won't be on the 600d. Live view + the articulated screen should be OK though. As for working distance and magnification, I'll just have to experiment and see what's best. Maybe I'll end up getting a Raynox 150 as well to try out.
At the moment using the 3mp EZ crop to get 150mm I've got no real room to crop further without the image quality suffering, so even shooting at 150mm with the new setup I'll have the ability to shoot at 18mp and crop a little more which will help. Even that by itself is a bonus. I eventually want to do a few canvas prints etc, so more wiggle room to crop would be good.

 

[HoppyUK]

I'm happy with this as I think in terms of image size and this this example when you reduce the image size (with a shorter lens) you get more D of F, and if you keep the image size the same and stop down you increase the D of F. This is what I would expect. When I did this sort of thing, every print I produced needed to have the magnification identified so I am just in the habit of thinking in terms of image size rather than angle of view

I still don't follow the earlier example where the the same size image on the larger sensor is give three times the depth of field.

You're right when you say depth of field is all about f/number and magnification but that's an over simplification - because under the umbrella of magnification there's focal length, focusing distance, and sensor size, plus print size, viewing distance and the standard of acuity applied. (You could also argue f/number is magnifcation too, as it's the diameter of the aperture.)

Fortunately, the last three factors (print size, viewing distance and standard of acuity) have been universally standardised for decades, so at least we're all on the same page there, but it's important to know about print size and viewing distance, because with digital it's so easy to zoom in for 100% viewing and that changes everything.

Along the same lines, depth of field can only be determined from the final image when output for viewing (print, on screen etc), and not at the moment of capture - that's why apparently identical images at sensor level can have different depths of field according to how they're finally rendered.

 

[myotis]

You're right when you say depth of field is all about f/number and magnification but that's an over simplification - because under the umbrella of magnification there's focal length, focusing distance, and sensor size, plus print size, viewing distance and the standard of acuity applied..

Yes, its deliberately an over simplification, because, well... to make it simple.

The starting point as you say needs to be the output size and viewing distance of the final image, and then work backwards, but the other things you describe all have an effect on the magnification. So from a simplistic practical point of view if you need to increase depth of field, you reduce the image size, or/and decrease the aperture size. If you want to decrease depth of field you increase the image size or/and increase the aperture size. So when considering focal lengths of lenses, or sensor size etc you just need to think about this in terms of how it affects the magnification etc.

I, obviously, think its a good working rule of thumb, for managing depth of field.

 

[Phil V]

A tiny sensor device like a phone or compact will not have a 100mm f2.8 macro lens, it'll have a 5mm something or other. Put the 100mm f2.8 on both and stand in the same spot and take two pictures and the smaller sensor device will give you... drum roll...

a. Less DoF.
b. More DoF.



I know which my money is on and why

As you said, we wouldn't use a 100mm lens on a cameraphone sized sensor.

I don't want to get dragged into 'equivalence' as it is a complicated thing for some to get their head around...

My post was based on subject distance / field of view. At which point my assertion makes sense.

If you start putting numbers on it that aren't actually used but prove the physics, it gets ridiculous.

 

[GardenersHelper]

Sorry but depth of field has a very strong relationship to sensor / film size.

It's almost impossible to create an OoF background at normal distances on a phone cam, and creating any kind of depth of focus on a 10x8 requires stratospheric f no's.

I agree entirely with this. So just a couple of side comments on some details in what follows.

As you said, we wouldn't use a 100mm lens on a cameraphone sized sensor.

Some smartphone cameras use 1/2.3" sensors. Many bridge cameras use 1/2.3" sensors, and a number of them go beyond 100mm - that is 100mm absolute, not equivalent. For example the Panasonic FZ330 goes to 108mm (600mm equivalent) and the FZ80 goes to 216mm (1200mm equivalent).

My post was based on subject distance / field of view. At which point my assertion makes sense.

Absolutely. FWIW I find the field of view perspective much more useful to consider.

If you start putting numbers on it that aren't actually used but prove the physics, it gets ridiculous.

As it happens the numbers I used in the examples in my responses here and here (focal length, aperture and focus distance) were chosen so as to be realistic, as in usable on existing kit. (And I think both examples demonstrate your point that depth of field has a very strong relationship with sensor size.)

 

[petersmart]

If you use extension tubes you can increase the magnification by allowing the lens to move closer to the subject. Here are 3 examples of my 70-300 lens @ 300mm with minimum focus distance with no tubes, a 16mm tube then an additional 10mm tube (total 26mm).

No tube


16mm tube


16 + 10mm tubes (26mm)


But a dedicated macro lens allows much closer focus here is my 90mm macro lens with no tubes, not the best of shots but demonstrative only.

Definitely agree with that as I also use my zoom lenses (as well as primes) with extension tubes.

They work perfectly when combined with a tall flashgun on the camera as fill in:

​

Taken with set of Kenko extension tubes and a Canon 70-300mm L lens at 300mm (as far as I remember).

It was taken on a Canon 1Ds MkII with a full set of tubes giving a 68mm extension.

Since I used flash and there was bright sunlight it meant that the shutter speed was 1/250th sec so the aperture was about f22 which increased the DOF a bit.

 

[petersmart]

Yes, except zooms are funny beasts and they don't all behave the same way with close up lenses.

I have just looked and with my Nikon 18 - 200 zoom with a Canon 500d close up lens (much less powerful than your Raynox) on an APS Nikon. I can zoom from a subject size of about 10" long to one of 2.5" long filling the frame, while keeping approximately the same distance from the subject. But it needs more refocussing, and slight adjustments to the working distance than I would have hoped for.

I found that with my 70-300mm L lens and extension tubes it was easier to focus initially by using the zoom ring rather than the focus ring and then do the back and forward body movement to get the focus as sharp as possible using manual focus.

Auto focus in this instance was pretty useless.

 

[myotis]

I found that with my 70-300mm L lens and extension tubes it was easier to focus initially by using the zoom ring rather than the focus ring and then do the back and forward body movement to get the focus as sharp as possible using manual focus.

Auto focus in this instance was pretty useless.

That sounds reasonable. I suspect that everyone needs to find what works with their particular set up, and what they are photographing.

Yes, autofocus has problems with close ups as the subject/background/ foreground tend to be too complex for it to work out where to focus, when there is so little depth of field.

 

[Forkbeard]

I got a chance to take my new setup for a spin (pardon the pun) and here are a few results. They aren't perfect but I'm getting better, although I'm struggling with lighting so that will be my next challenge - getting the flash right:

IMG_0204 by James Howard, on Flickr

IMG_0212 by James Howard, on Flickr

IMG_0209 by James Howard, on Flickr

IMG_0213 by James Howard, on Flickr