Sebastião Salgado: Genesis Exhibition

[davidb]

Nice shot David although it does seem to be loosing focus at the front and the antenna. But then it is difficult with such close shots.

What lens did you use? I tend to use the Canon 28-135mm which does have macro capabilities but haven't yet got a really all-over-sharp picture. I'm experimenting with Aperture priority and hope I'll hit on the right formula.

[Mike Farley]

What lens did you use? I tend to use the Canon 28-135mm which does have macro capabilities but haven't yet got a really all-over-sharp picture. I'm experimenting with Aperture priority and hope I'll hit on the right formula.

The 28-135 does not have the best reputation. Its an old design which predates digital and sometimes older lenses do not do so well due to the differences in the way that film and sensors record light. I would also doubt whether it has true macro 1:1 capabilities; typically such lenses have a more modest close up performance. In such cases, macro is more of a marketing term.

[davidc]

I used the 100mm f2.8 Canon macro and used a custom flash rig to apply even lighting - that let me get more DOF and still keep it sharp. The problem with macro is, as you say, on small scales getting two opposing "depths" in focus. In fact, I doubt it's actually feasible to get it truly sharp without focus stacking and that wasn't possible with a moving target.

Consider the exif - Canon 550d, 100mm Macro f2.8, f/10, iso 400 and 1/200th shutter

The f-stop I've used is already beyond the diffraction limit of the camera and pushing it further would see rapidly diminishing returns so I'd never get it as sharp as I'd want. Even on full frame the diffraction limit for our respective cameras is about f/10 anyway so pushing to maybe f/16 would be possible but require so much extra light I'd be less inclined to blast the creature with so much flash!

Long story short, you're absolutely right about the DOF but I don't think it's an issue
In a studio setup where the animal is dead or chilled then you have all the time in the world to take multiple shots and stack them but if you are out and about that's not possible. I also don't think the small areas that aren't in total focus detract from the image

[Mike Farley]

The f-stop I've used is already beyond the diffraction limit of the camera and pushing it further would see rapidly diminishing returns so I'd never get it as sharp as I'd want. Even on full frame the diffraction limit for our respective cameras is about f/10 anyway so pushing to maybe f/16 would be possible but require so much extra light I'd be less inclined to blast the creature with so much flash!

It's a trade off. Sometimes you need to go beyond the diffraction limit to get the required DOF. Losing a bit of resolution is not something to get too hung up about in my opinion if it gives the result you want. There are quite a few successful macro shots out there which have been taken at f/22 or even f/32.

[davidc]

Do you have an example? I've not seen any and focus stacking seems to be the prevailing way to get extreme DOF at macro scales rather than tiny apertures. I've experimented myself using it and it's definitely visible

[Mike Farley]

Do you have an example? I've not seen any and focus stacking seems to be the prevailing way to get extreme DOF at macro scales rather than tiny apertures. I've experimented myself using it and it's definitely visible

Here you go, although I am not sure how much you will be able to tell from a low resolution JPEG. There are undoubtedly other examples on flickr, but I have not specifically looked.

viewtopic.php?f=6&t=325&p=1707&hilit=100+macro#p1707

viewtopic.php?f=6&t=224&p=1155&hilit=100+macro#p1150

I have tried focus stacking in PS CC, but that is an aspect to which Adobe definitely needs to devote more attention. That might be a bit too radical for Adobe, ensuring what you already have works properly before introducing new features; its probably does not tick any marketing check boxes. I did not try the Helicon software, mainly because I thought it was way too expensive for the limited use to which I would put it.

[davidc]

I've used free focus stacking software in the past and been pleased with the results, I think it was called Zerene if memory serves.

[Mike Farley]

I've used free focus stacking software in the past and been pleased with the results, I think it was called Zerene if memory serves.

There's a free 30 day trial, but it is a commercial product. Apart from expenditure on something I knew I would not use much, I was not keen on the policy of charging extra for commercial use.

http://zerenesystems.com/cms/stacker/docs/purchasing

[davidb]

I have a Canon 60mm macro. I've not used it for a while because I wasn't getting good shots from it.

But having recently changed from P to AV on my cameras it may be worthwhile trying it again, although, as it's an EFS lens it is not compatible with the Canon 1DX.

The depth of focus is not a major problem, as Mike says, as good as if not better than some of the same butterfly I've taken. Although I wonder how it would look projected?

Err, haven't we strayed off the path somewhat here?

[Mike Farley]

I have a Canon 60mm macro. I've not used it for a while because I wasn't getting good shots from it.

This lens gets good reviews. Maybe you have a bad copy? What is it about the results which disappoints you?

Err, haven't we strayed off the path somewhat here?

Fascinating, isn't it? That's the way conversations go, distinctly non linear.

I wonder where it will end up?