HSS for macro

pjm1

pjm1

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Paul
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This is probably a silly question, but...

I've just finish cannibalising a pringles tube (thanks @Carlh et al) and have now made a second home-made flash adaptor to go with my much bigger and multi-purpose lampshade / baby-muslin diffuser. This new one comprises rings of pringle tube sections (for strength) held together with heavyweight (high gsm) white paper and sellotape. I will be getting more tape (both white to reflect and black insulation tape for the outside) in due course. It's not elegant, but it seems to do a good job of redirecting my on camera flash down to just the right place in front of my 50mm lens with Raynox attached. Best of all, I no longer need one hand to hold my flash off camera:

XlcvLba.jpg


Now, my flash (well, one of them - not the one in shot above) is HSS compatible and it got me thinking: if light quantity isn't an issue, is there any downside to using a high shutter speed (e.g. 1/500) and HSS for macro shots? I'd assume in most cases the real issue IS quantity of light, so HSS is a stupid idea as it just reduces the flash power and you're letting less ambient in with the high shutter speed. BUT... if I'm shooting outside where light quantity isn't a problem, does HSS - or more specifically, using a high shutter speed - make some sense for macro shots? The problem I'm wondering whether it helps solve is camera shake - especially if we're shooting in windy conditions.

Anybody have any views or experience with this?
 
daugirdas said:
Wind will move the subject out of focus and potentially out of frame. How do you plan to compensate for that with flash?
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Yes, of course you're dead right with the wind - we're basically screwed when it's blowy! But the camera shake question... I realise the best answer is "improve your technique" but my technique will improve to "acceptable" more quickly if I'm trying to shoot at 1/250th than 1/160th :)
 
Now you will have a free hand to hold (maybe) the leaf/plant/whatever.
 
Graham said:
Now you will have a free hand to hold (maybe) the leaf/plant/whatever.
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Yes - I tried that and because I was so stoked about constructing my flash adaptor I was still shaking with excitement... needless to say my intervention was more damaging than the occasional gust. I've now had a gin & tonic so my hand should be steadier ;)
 
looking good paul! wasn't my idea about pringles tube anyway, was another user, which i have forgotten so if he's reading this - I thank him for the idea :)
 
Graham said:
Now you will have a free hand to hold (maybe) the leaf/plant/whatever.
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I often do this... hold leaf with one hand and then rest lens on that hands wrist. As shooting 1 handed is very hard can be done and I have done it in the past.

As to OP... HSS not sure why you need >1/200s but HSS is something I have thought about but think it is used in portrait work to overpower the sun generally.
 
Tintin124 said:
I often do this... hold leaf with one hand and then rest lens on that hands wrist. As shooting 1 handed is very hard can be done and I have done it in the past.

As to OP... HSS not sure why you need >1/200s but HSS is something I have thought about but think it is used in portrait work to overpower the sun generally.
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Hi Bryn... I do a fair bit of one-handed shooting (that sounds very wrong :eek:) but maybe that's also a reason why my shots aren't always the steadiest?!

I wondered if >1/200th might remove the chance of camera shake, especially if only holding the camera with one hand? Given the magnifications we're dealing with (I think you made that point to me), the usual rule of 1/focal length isn't the best guide for sharp shots?
 
pjm1 said:
Hi Bryn... I do a fair bit of one-handed shooting (that sounds very wrong :eek:) but maybe that's also a reason why my shots aren't always the steadiest?!

I wondered if >1/200th might remove the chance of camera shake, especially if only holding the camera with one hand? Given the magnifications we're dealing with (I think you made that point to me), the usual rule of 1/focal length isn't the best guide for sharp shots?
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I did indeed make that point and its still correct lol... what is the maximum shutter sync speed you can use without HSS? 1/200s is easily enough to stop handshake however unless your really really shaking then you shouldn't shoot one handed oooo eeerrrr missus.
 
Sadly my camera's x-sync is 1/180th but the highest I can actually set (at or below that) is 1/160th. Probably should be enough anyway I'd guess, especially if using a 50mm - with my DCR-250 (8 diopter, i.e. 3x) that kind of equates in my simple mind to 150mm, so as long as my shutter speed is faster than 1/150th I should be ok.

So maybe the HSS is only of any use if we're using longer f/l AND a Raynox or super telephotos (300mm+)? Not that I'd fancy using a 300mm lens for macro ;)
 
pjm1 said:
Sadly my camera's x-sync is 1/180th but the highest I can actually set (at or below that) is 1/160th. Probably should be enough anyway I'd guess, especially if using a 50mm - with my DCR-250 (8 diopter, i.e. 3x) that kind of equates in my simple mind to 150mm, so as long as my shutter speed is faster than 1/150th I should be ok.

So maybe the HSS is only of any use if we're using longer f/l AND a Raynox or super telephotos (300mm+)? Not that I'd fancy using a 300mm lens for macro ;)
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Its not a convertor so doesn't increase your focal length... it shortens if anything (https://www.flickr.com/groups/raynoxdcr250/discuss/72157631389685326/). Pick up a magnifying glass you can't see further with it, it actually reduces your distance focal viewing but it does increase the size of the viewing object.

Saying that if you put it at the back of your lens before sensor it may increase the focal distance. lol
 
Sorry Bryn, I wasn't being very clear - in my mind it has the effect of using a longer focal length lens but with the same MFD... in reality it is the same focal length but with a MUCH shorter MFD (and therefore a far higher magnification). But... the purpose of equating it to a 150mm lens was simply to make the point that you'd need a faster shutter speed than I might expect for a 50mm lens because of the additional magnification of the image.

My way of looking at it is probably even more confusing but it made sense at the time!
 
pjm1 said:
Sorry Bryn, I wasn't being very clear - in my mind it has the effect of using a longer focal length lens but with the same MFD... in reality it is the same focal length but with a MUCH shorter MFD (and therefore a far higher magnification). But... the purpose of equating it to a 150mm lens was simply to make the point that you'd need a faster shutter speed than I might expect for a 50mm lens because of the additional magnification of the image.

My way of looking at it is probably even more confusing but it made sense at the time!
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:D Now I get you and there will probably be a mathematical relationship between magnification and shutter speed required but sure its complex and way over my head so maybe your thinking is a good idea. Though saying it I coped fine with 55-250 at 250mm and raynox 250 @ 1/200s which by the logic applied above should be 1/750s to stop hand shake.

But this is all conjectures and if this is the way for you to work it then go with it but before going HSS try 1/180s at all focal lengths on your zoom before applying HSS logic.
 
You want to avoid using HSS for macro (although I've never really experimented with it). The reason being is that by using high aperture (for greater DoF) and high shutter speed (to reduce camera shake) you will usually get very little light hitting the sensor. In fact, without flash you will probably see a dark frame (I often get a few dark frames in between shots if my flash is taking it's time to recycle). This means that the exposure time is actually the duration of the flash pulse rather than the shutter speed In this way it usually freezes motion and avoids any camera shake issues.

At standard synch speeds (1/200s for canon, I believe Nikon and most other brands are 1/250s) it works like this:
  • The front curtain of the shutter opens fully, the sensor is exposed
  • The flash fires
  • The rear curtain closes
  • The curtains reset
With this method, the flash light duration is less than the amount of time the shutter is open, and the image is exposed only for the length of time the flash has fired for.

At High speed synch it works like this:
  • The flash fires (or pulses)
  • The front curtain begins to open
  • The rear curtain begins to close
  • The front curtain opens fully
  • The rear curtain closes fully
  • The flash stops pulsing
  • The curtains reset

This means that only part of the sensor is exposed at any time, which is the space between the two curtains as one opens and one closes behind it; but the sensor is never fully exposed (this is how those high shutter speeds are achieved). However, as the flash is our main and likely only light source (due to the high shutter speed and narrow aperture) the exposure time is the length of the flash pulse whilst the curtains are open. In this scenario you can assume the flash is on for the full time of the shutter being open (or the actual shutter speed). In practice this works out to be longer than the single quick flash whilst the shutter is open at slow synch speeds.

In effect, HSS actually increases the exposure time and as a result is worse at freezing any movement, either of the subject or through camera shake.

That's the theory anyway. As I mentioned, it's not something I have taken the time to play with.

Edit: Here's a good guide to HSS:

http://www.exposureguide.com/high-speed-sync-flash.htm
 
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