Spider Face

[delgado]

I'm not sure but I think this might be a Lace Webbed Spider (?). It was found expired in the bathroom. It was given a wash and I left it quite a while afterwards to dry but either it still hadn't dried or it's body has a naturally oily look to it...I might have to look at it again later. I have awful trouble tidying up murky backgrounds, especially around hairs - is there a really obvious way of doing that I'm missing? I've tried using a lighten brush with limited success. I think part of the issue is the light needs to be more firmly controlled and perhaps the stack could do with going deeper.

[rjlittlefield]

Can you spell out in more detail what you mean by the words "murky backgrounds"?

In the image posted here, I see some hairs on top of the head that look sharp and clear, and I see some other hairs farther to the right that look fuzzy and washed out, like they're being seen through fog.

I also see some variations in background brightness and color between and around the sharp hairs that look like typical PMax halos resulting from OOF info leaking into the final image.

I think there are at least two things going on here, because I can't think of any one thing that would cause both the fog and halos.

Which of these issues are you concerned about, or something else?

Regarding the oily appearance, you might try washing in alcohol instead of water. If that doesn't do it, you might have to graduate to something like acetone.

--Rik

[delgado]

Thanks for your thoughts on this. Yes. it's largely the fog effect I struggle with, the slightly out of focus hairs take on an 'impressionist' appearance viewed close up. I should point out I have made some clumsy attempts to clean up the background between and around the hairs so the final result is partly me and I need to get better at these cleaning up aspects of technique .

I think I will try this stack again having washed the spider in some alcohol as you suggest and going a little further back this time and see if that helps.

For diffusion I'm using a semi-translucent cap from a toothpaste tube, with another similar cap inside it and toilet paper sandwiched between the two. I use two flashes on 1/8th power.

Perhaps this is a silly question - in this situation, is it possible to diffuse incoming light too much? This is one of the better results but I have noticed a lot of my tests have suffered from a lack of contrast (the individual frames from the camera rather than the stack) - I'm not sure if there is any link between the two. I have made sure there is nothing reflective between the objective and the sensor so I don't think that's the problem.

[rjlittlefield]

Perhaps this is a silly question - in this situation, is it possible to diffuse incoming light too much? This is one of the better results but I have noticed a lot of my tests have suffered from a lack of contrast

There are a couple of things that can go wrong here.

Contrast can easily be cut by stray light bouncing around inside the lens and camera. This problem is sometimes made worse by adding diffusion, when the added diffusion causes more light to enter the lens from outside the subject field. To defend against this problem, remove the camera from your lens and extensions and look inside by eye while pointing the lens at a large bright field. Ideally you will see only light coming straight through the lens, but it's very common to see reflections from the sides of extension tubes and adapters. Those reflections must be flocked or masked or the scattered light will cut your contrast. Shading the lens can also help a lot.

In addition, contrast can be cut by adding diffusion if the added diffusion results in more glare bouncing off the surface of the subject. (Think about looking into a pool of water on an overcast day, versus the same pool on a bright sunny day with the sun behind you. You'll see a lot less subsurface detail on the overcast day, when there's a lot of light bouncing off the surface into your eyes.)

Otherwise the issue depends on whether contrast in your subject arises from pigmentation or shadowing. If it's from pigmentation, then adding diffusion will not cut contrast (except for the effects noted above). But if it's shadowing, then more diffusion will brighten the shadows and cut contrast that way.

About the "impressionist" appearance of the soft hairs, I agree that those appear to be slightly out of focus. Shooting a deeper stack will get more in focus. Sometimes a deeper stack will introduce other problems, but if you have the additional frames, you can always decide to not use them.

By the way, it's common for background hairs to lose contrast when they are near the edge of a foreground structure, particularly if the foreground structure is light in tone. This happens because when the hairs are focused, they are also partly occluded by out-of-focus foreground. Light from the OOF foreground gets added to whatever is coming from the in-focus hair, and if the hair is dark, the OOF foreground contribution can cut the contrast by quite a lot.

--Rik

[delgado]

This problem is sometimes made worse by adding diffusion, when the added diffusion causes more light to enter the lens from outside the subject field.

Ah...that's interesting. It occurs to me that about 2/3 of the length of my diffuser is actually behind the subject. So it's possible quite a bit of light is getting bounced around behind the spider and then projected around it and back into the lens? Thinking about it, I have noticed in other set-ups with the ping-pong diffusers that these often only extend to just beyond the subject...

I'll have another check inside my bellows too, I did put some matt black paint on everything with a shine that I could find quite recently but it's worth another look.

Thanks very much for you advice, most 'illuminating'!