Depth of Field with 18-55mm kit lens

Matt_C

Matt_C

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Matt
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Hello all,

I took the snap below with my Canon 550D and wanted to see a slightly stronger depth of field on the kit lens.

Is there any way to get better (not perfect naturally) dof with the kit lens?


IMG_0421 by MAC_1985, on Flickr
 
By 'stronger depth of field' I assume you mean subject in focus and background blurred?
That's a shallow depth of field.
The depth of field is the 'slice' of the scene that's in focus, the shallower it is less of the foreground and background will be in focus, the deeper it is, more will be in focus.
Does that make sense?
The lens aperture controls the DOF and it looks like you were already wide open at f3.5 so there's not much else you can do other than get some distance between the subject and the background. (y)
 
Whoopsie. There's lesson 1 learnt on clarification of terms! Sorry!

So, if l had used a telephoto lens, might that have produced a shallower dof?
 
In my experience yes, but you may need a decent bit of glass. Cheaper lenses might do it but not sure??
you want this effect basically (shot with a 70-200 F4 IS L) excuse the harsh sun lighting pls ;):
247654_10151169300354294_1586746294_n.jpg
 
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The only other thing you can do is zoom your lens to it longest focal length (55mm in your kit lens)
And then zoom with your feet!
 
^ The problem then is that the lens will change the aperture to f5.6 which will be no good at all for shallow dof shots.
 
You need to save your coppers and by a faster lens. Or a cheap tele zoom i suppose.
 
Been learning this myself recently. Bought myself a Canon 600D and have both the 18-55mm and 55-250mm kit lenses. One of the big things I wanted to do with it was take shots with the nice Bokeh in the background.

It's not easy with kit lenses, but I'm getting there...it CAN be done.
 
On APS-C f5.6 at 85mm would give you more chance...

5-6-85.jpg


There's not much chance of moving gravestones about to get them forward of the background for best effect though.
 
woof woof said:
On APS-C f5.6 at 85mm would give you more chance...

There's not much chance of moving gravestones about to get them forward of the background for best effect though.
Click to expand...

+1 i just got a 15-85 and gets good dof at 85mm but nothing beats the 50mm at 1.8 for beastly bokeh

IMG_4658.jpg
 
cotty332000 said:
If you want shallow dof just spend £60 on a s/h 50mm f1.8 prime!(y)

Stick it on f1.8 fire away job done!:LOL:
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That is an excellent suggestion, but with a xxxD body you're limited to a max shutter speed of 1/4000 second which in good light could stop you using the widest apertures. In a lot of situations though, what you've said is I think the answer :D

I may have an even cheaper suggestion... buy a used wide aperture manual legacy lens and a cheap adapter. A 50mm f1.8 or even a 135mm f3.5 + cheap adapter would be fun :D and cheap :D
 
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Matt_C said:
Whoopsie. There's lesson 1 learnt on clarification of terms! Sorry!

So, if l had used a telephoto lens, might that have produced a shallower dof?
Click to expand...

No. It's often said that telephotos deliver less depth-of-field than wide-angles, but it's not true. Not if the subject is framed the same size.

Calculate it here http://www.dofmaster.com/dofjs.html If you input say a 50mm lens at 10ft, then change that to a 100mm lens at 20ft and shoot at the same aperture, the main subject will be framed the same size in the image and DoF will be the same too.

What does change is the field of view, which is narrower with a longer lens and this cuts out a lot of the background, which then appears relatively larger, and this often gives the impression of shallower DoF, but it's not the same thing.
 
Yawn.

Longer lenses may not actually give shallower DoF for the same framing but IMVHO this doesn't really matter because the look that longer lenses give makes it appear that they do and how the image looks and is perceived is what matters not measurabatory hair splitting and ever more posted links to internet DoF tables.

All in MVHO of course :D Other opinions are available :D
 
woof woof said:
Yawn.

Longer lenses may not actually give shallower DoF for the same framing but IMVHO this doesn't really matter because the look that longer lenses give makes it appear that they do and how the image looks and is perceived is what matters not measurabatory hair splitting and ever more posted links to internet DoF tables.

All in MVHO of course :D Other opinions are available :D
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Sorry if this is keeping you up Alan, but it is not hair splitting at all and is an important distinction to know and understand. And it makes a difference because the perception of shallower DoF with longer lenses is an illusion and does not always apply - it depends entirely on the nature of the background.
 
Matt, listen to Richard if you want to know what will actually work to get the results you want. (y)

Taking that shot at 55mm on your kit lens would result in a deeper depth of field (more background in focus) because you would be limited to the narrower aperture of f/5.6.

Now, if you stayed stood in the same place and zoomed in to 55mm, then yeah, you might get slightly shallower depth of field. But you'd also have a completely different, very odd photo of the middle part of a tombstone - which is probably of less use to you. ;)
 
LOL James ;)

The point I was really trying to make, is that using a longer lens and moving back in the hope of reducing depth of field will result in a completely different picture, but the only thing that will not have changed is the DoF!

Back to the OP, if shallow DoF is something you want to use a lot then the best way is to start with a camera with a larger sensor. Full-frame cameras deliver the equivalent of a bit over one stop less DoF compared to crop format - when the subject is framed the same, from the same distance, at the same aperture.

If that's not an option, then the only way to go is with a lower f/number lens, probably a prime around f/2 or f/1.4. That would do it, as suggested previously.
 
HoppyUK said:
LOL James ;)

The point I was really trying to make, is that using a longer lens and moving back in the hope of reducing depth of field will result in a completely different picture, but the only thing that will not have changed is the DoF!
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The total depth of field will not have changed, but the front to back split will have changed

The longer the focal length, the the dof split gets nearer and nearer to 50/50, the shorter the focal length, it gets nearer to a 1/3 to 2/3 split.
 
Matt_C said:
Hello all,

I took the snap below with my Canon 550D and wanted to see a slightly stronger depth of field on the kit lens.

Is there any way to get better (not perfect naturally) dof with the kit lens?


IMG_0421 by MAC_1985, on Flickr
Click to expand...

You could try playing around with photoshop; select everything apart from the main subject and blur the background.
 
The kit lens is capable of producing some bokeh, it won't be as nice as large aperture lenses, but it is possible: zoom to 55mm, f5.6 and get as close to your subject as you can focus with background as far away as possible.

People are forgetting the 3rd factor that produces shallow DoF: how close is the focal point. suggesting to buy new gear is the sin of this forum.

At 18mm f3.5 the subject is smaller in your frame (hear me out Hoppy :) ). The minimal focusing distance of the lens doesn't change, so you can't get the same framing as at 55mm.

so this photo was taken on a 18-55mm kit lens, f5.6, focusing as close as the lens allows, with background around 3 meters away:

Back Garden by wuyanxu, on Flickr
 
wuyanxu said:
suggesting to buy new gear is the sin of this forum.
Click to expand...
:plus1:

I dont think the lighting helps the OP's picture much either :shrug:
 
mortimerhill said:
The total depth of field will not have changed, but the front to back split will have changed

The longer the focal length, the the dof split gets nearer and nearer to 50/50, the shorter the focal length, it gets nearer to a 1/3 to 2/3 split.
Click to expand...

Not really. The front/rear DoF split is a function of distance, not focal length.

When you're really close, like a close-up of a flower or macro, the front/rear split is around 49:51%. When shooting at distance, like a landscape, it's more like 1:99.9%, with everything sharp from the foreground to the moon.

The rule of thumb to 'focus one third in' (ie, 33:66%) is a handy reference but that only works for regular kinds of subjects like people groups (not too close, not too far away) where the front and rear limits are clearly defined.

To be really picky, when extremes are compared, like a 20mm lens from very close range and maybe a 200mm lens from much further back, there is indeed a little less DoF with longer lenses. But it's not much and that kind of situation is very rare in practise.

wuyanxu said:
The kit lens is capable of producing some bokeh, it won't be as nice as large aperture lenses, but it is possible: zoom to 55mm, f5.6 and get as close to your subject as you can focus with background as far away as possible.
Click to expand...

Yes, but the picture would change completely, with just a small part of the cross in the frame.

People are forgetting the 3rd factor that produces shallow DoF: how close is the focal point. suggesting to buy new gear is the sin of this forum.

At 18mm f3.5 the subject is smaller in your frame (hear me out Hoppy :) ). The minimal focusing distance of the lens doesn't change, so you can't get the same framing as at 55mm.

so this photo was taken on a 18-55mm kit lens, f5.6, focusing as close as the lens allows, with background around 3 meters away:
<snip>
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Tend to agree, but in this case it's the only solution to the OP's question.
 
I've been experimenting with DoF with my 18-55mm kit lens recently as well. I was in Costa coffee this morning and took this:

8409434920_eb91bc0aa6_c.jpg



I think it's probably the best that I've taken with a kit lens, but it does show the possibility of getting somewhat decent bokeh with the kit lens.
 
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Forbiddenbiker said:
Nice example Mike:clap:.... I cant see your exif details, which focal length is that?
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I think that was around 28mm. I think it was a lucky shot really, but the rule of thumb on the kit lens definately is to open the aperture up as much as you can and get closer to the subject
 
Thought so, it looked in the middle somewhere, just long enough to keep the kit lens at the f3.5 wide open end as you suggest.

Users should also notice that the shallow DoF is NOT a precise slice of an area either side of the focal plane, which can be noticed at wider apertures.
In this case the slightly spread DoF means it renders close objects as near in focus or clearly identifiable like the two cup lids and table.
The only way round this is careful selection of subject matter that will work for your kit lens DoF limits, rather than against.
 
This is one from when I first got my D3100 and was just messing around learning what things do. I know it's not a great shot but does show that you can get some shallow DOF with the kit lens, but you do need to be fairly close to your point of focus.


DSC_0035 by Jonjay3100, on Flickr
 
this was with a 18-55 at 33mm and F/5.6

IMG_1846.jpg
 
Seeing examples where the subject is close to the camera are not really proving much as to be fair a small sensored compact can achieve low DoF in those scenarios.
 
Another thing that sometimes helps (picking up on the principle behind the close focussed narrow DOF shots) - rather than place primary focus on the cross itself if the OP manually focussed a little closer so that the cross was still in the main DOF it would throw the background out of focus a little more. e.g. if the cross was 2ft away from the camera, manually focus on an imaginary spot 18 inches away - experiment with the actual distances - and DOF tables/apps can help here.

Not a cure all but it's helped me a lot.........
 
<a href="http://www.flickr.com/photos/92443340@N08/8395146145/" title="test image by wasimwazir, on Flickr"><img src="http://farm9.staticflickr.com/8096/8395146145_d5907c6a47.jpg" width="500" height="333" alt="test image"></a>

heres mind....its edited in ps

if this link works:

http://www.flickr.com/photos/92443340@N08/8395146145/


by the way i think i used 18mm with f3.5
 
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Although it can be done to a certain extent you are in an uphill battle. Just buy a 50 1.8 used if you really want low DoF, they are very cheap and perfect for your needs.
 
ernesto said:
Although it can be done to a certain extent you are in an uphill battle. Just buy a 50 1.8 used if you really want low DoF, they are very cheap and perfect for your needs.
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Was thinking about the nifty myself, but then decided that I would get much better DoF with the 1.4. Still waiting for it to arrive, so more than a little giddy with excitement!
 
ernesto said:
Although it can be done to a certain extent you are in an uphill battle. Just buy a 50 1.8 used if you really want low DoF, they are very cheap and perfect for your needs.
Click to expand...

It's true. Getting very much in the way of shallow DoF effects with a kit lens, especially on a crop-sensor camera, is difficult at normal shooting distances, though DoF reduces dramatically as you get closer. And also at low f/numbers.

A quick example: Canon 550D (1.6x crop factor), 30mm lens.

Subject at 10ft, at f/5.6 DoF is 253cm. At f/1.4 DoF is 55cm.
Subject at 8ft, at f/5.6 DoF is 152cm. At f/1.4 DoF is 35cm.
Subject at 6ft, at f/5.6 DoF is 82cm. At f/1.4 DoF is 20cm.
Subject at 4ft, at f/5.6 DoF is 36cm. At f/1.4 DoF is 8.7cm.
Subject at 2ft, at f/5.6 DoF is 8cm. At f/1.4 Dof is 2.1cm.
Subject at 1ft, at f/5.6 DoF is 2cm. At f/1.4 DoF is 0.5cm.

Lots of stuff about depth of field, plus on-line calculator at DOFmaster http://www.dofmaster.com/dofjs.html
 
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