Question: Preferred DOF with reasonable working distance?

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Kyle from Carolina
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Question: Preferred DOF with reasonable working distance?

Post by Kyle from Carolina »

That subject line might be a bit vague but here's what I'm trying to figure out:

I would like for more of my shots to fit these criteria:
1) animal fills the frame
2) Extremely crisp details on eye/face
3) Entire body in focus

Sounds simple, but I have the hardest time with small snakes and largeish salamanders and I usually have to compromise on one of the above criteria. Usually to get the entire animal in focus, I have to back up considerably, at which point the animal doesn't fill the frame. I then have to crop down and I lose crispness. When I fill the frame with the critter, at least some part of the animal lies outside of the DOF. I usually shoot with a sigma 105 mm, handheld. When I switch to my kit 18-55, I can get a much deeper DOF but I have to be pretty close for the animal to fill the frame, which is not ideal with venomous critters.

Here's an example of a photo I am generally happy with but I would have liked to get the tail in focus too:

ImageWestern Massassauga (Sistrurus catenatus tergeminus) by Kyle JW, on Flickr

And a neonate western sauga from the same day:

ImageWestern massasauga (Sistrurus catenatus tergeminus) - Neonate by Kyle JW, on Flickr

I have a particurlary difficult time when the animal is oriented long-ways and facing me, like this three-lined salamander:

ImageThree-lined salamander (Eurycea guttolineata) by Kyle JW, on Flickr

All other issues aside, how would you approach the situation to achieve the three things listed above?
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Stohlgren
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Re: Question: Preferred DOF with reasonable working distance

Post by Stohlgren »

There is a lot of personal taste involved when it comes to DOF, and I don't have any real solutions for you if you really desire the entire frame to be in focus, but I am going to make a case that it is not really necessary.

So, as you've already noticed, DOF decreases with increasing magnification. That is why you are losing DOF when you get closer to the subject with your macro lens. When shooting small snakes and salamanders, this is always going to be an issue. You can close down your aperture to get a greater depth of field, but you will lose sharpness due to refraction. You will also never get enough depth of field to get an entire snake/salamander in focus when they are facing you, as in the last photograph you shared. Your only option there would to be to get into focus stacking, which can be very tricky with fidgety subjects, and probably not worth the effort.

For my personal tastes, I don't actually like the whole subject to be in focus in most cases. I think the first shot you posted is pretty good. The viewers eye is drawn to the eye of the snake. If you stopped down the aperture to get more of the snake in focus, your photo would lose that focal point. If you must have the whole subject in focus, you are going to have to pose the animal on a narrower plain, which doesn't usually work for elongate critters like snakes and salamanders.

For field guide style shots, if you get get at about a 45 degree angle from your subject and use an aperture from around f/13 to f/22, depending on the size of the subject (I rarely go above f/16 personally), you will get enough DOF without losing that visual draw to the subjects eyes (which should be in sharp focus).

f/13 - The head is in focus, while the body behind it is not, which helps the head stand out and draws the viewers eye, yet there is still enough detail in the whole body to be a field guide shot. (When photoing a jingle-tail, if you want the rattle in focus, try to pose the snake with the rattle on the same plain as the head. If you are taking in situ shots, you will just have to take what the snake gives you)
Image

f/13 - The snake is a little more spread out causing the tail to fall out of focus, but it is not distracting.
Image

For more artistic shots, like having a salamander oriented towards you, just use the lack of DOF to your advantage to help separate the subject from the background. These types of shots don't have to show all of the ID characteristics, so there isn't really a reason the whole thing needs to be sharp.

f/16 - The lack of DOF at this angle and pose helps separate the subject and really makes the cirri stand out.
Image

f/13 - Again, the lack of DOF helps the head stand out from the part of the body it is over lapping. If I shot this at f/32, the tail would still not likely be in sharp focus but it would cause the head to blend in with the tail. And the shot would suffer a loss of overall sharpness from refraction.
Image
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chrish
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Re: Question: Preferred DOF with reasonable working distance

Post by chrish »

Kevin nailed the explanation as usual, but I might add a point or two.

1. If you are aiming for "crispness", you should use the best lens you have. Your 105 macro is going to be sharper than your kit lens, but of course it does have a higher magnification (at the same distance) meaning DOF will be reduced.

2. If you endeavor to maximize sharpness (crispness), you should consider that your lens is not equally sharp at all f/stops. Sometimes stopping down more gives you more DOF but makes the image less sharp. That's why many of us prefer to stay in the f/11-16 range. With some research you can find the sharpness "graph" for your lenses and see where the sharpness is highest.

One other thing to consider is can I use higher ISO? With modern DSLRs, high ISO performance is pretty good. Often you can get a very good image at ISO 800 or higher. Using that higher ISO frees you to get higher DOF by using higher f/stops.

But, everything is a trade off. You just have to try to get the best balance you can.
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Kyle from Carolina
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Re: Question: Preferred DOF with reasonable working distance

Post by Kyle from Carolina »

Kevin,

Those type shots you posted are more or less what I was trying for. Well enough focus on the whole body yet the head still stands out. I'm often have trouble getting enough light for the 105 to shoot at smaller apertures (>f13) without using flash, which I don't normally use but maybe I should start. Those shots are great and I'm impressed how well the heads of those two snakes are distinguished from the background.

Chris,

When using the macro lens for a macroshot, I will often set the ISO to 400 because I can't tell a difference between that and 100, while I notice it starts to go grainy up over 800-1200. Thanks for the insight into the varying sharpness at different f-stops. This wasn't something I was aware of, although I've heard something similar for zoom lenses being less sharp when wide-open or at full zoom.

It sounds like mid-range f-stops in the low teens are closer to ideal for DOF and sharpness and I seldom shoot within that range because I can't expose them at shutter speeds faster than ~1/200. Gonna give this a try...

-Kyle
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Stohlgren
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Re: Question: Preferred DOF with reasonable working distance

Post by Stohlgren »

As Chris said, it is all about trade-offs. A smaller aperture lets in less light, so you will either have to slow down your shutter speed or up your ISO. This is why flash is a necessary component of macro photography (not to imply it has to be used in every macro photo). I shoot with natural light as much as I can, but that usually means using a shutter speed too slow to hand hold (making a tripod a necessity as well as a cooperative subject). Even then, I will often add in a touch of fill flash as I feel it adds a bit of contrast and helps bring out the colors of the subject more. When shooting something very small or in low light conditions like under a heavy canopy, there is often no choice but to use full flash (as in my salamander photos above) as I don't want to bump my ISO too high or have a very narrow DOF.
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Noah M
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Re: Question: Preferred DOF with reasonable working distance

Post by Noah M »

Kyle, I'm like you. And I recently bought an external flash with an omni bounce, and holy cow does that make a difference. Even on sunny days when my camera was self selecting ISOs below 400 with an aperture at f/13, I was getting harsh shadows and the like. A touch of fill flash softens those. Also, the flash can help keep your ISO down. I'd rather run through a pack of AAs then bump my ISO up. I think a lot of times ISO 400-800 is acceptable, and maybe its just psychological, but there is something nice about having a photo at ISO 400 and below. If you can get a well lit, properly exposed photo, with the subject filling the frame at ISO 100, then you've done all that you can do. I've been trying to keep my ISO around 200, which will save a bit on those AAs. I'm still learning the ins and outs of the flash, when and how much to use. I've got a few night shots way under exposed, and a few a day shots over exposed, but with practice I think I've have it together soon.

Sunny day, ISO 200, f/13 with the sigma 105mm macro, before owning the external flash. I don't like the shadows.
Image

Night, ISO 200, f/11, external flash. I like this picture much more than the one above.
Image
bgorum
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Re: Question: Preferred DOF with reasonable working distance

Post by bgorum »

Stohlgren and Chrish have really summed up the situation with depth of field quite well. The only other thing I can think of to add is if you really want that deep depth of field look, you could consider moving to a smaller format camera. 4/3 will provide more depth of field than dx, which will provide more depth of field than fx. Of course the smaller the sensor the larger the aperture at which it starts to become diffraction limited, so there really is no free lunch.
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Re: Question: Preferred DOF with reasonable working distance

Post by chrish »

captainjack0000 wrote:Sunny day, ISO 200, f/13 with the sigma 105mm macro, before owning the external flash. I don't like the shadows.
Image
Another solution for this problem is using a diffuser in sunlight.

Here I used a collapsible 30 inch diffuser to create diffuse shade on the snake -

Image

Here's a collapsible 12 diffuser disk for a smaller snake (with fill flash) -

Image

In this case, I used a white snake bag as a diffuser between the sun and the snake -

Image

Here, I simply put the snake in the shade created by the car -

Image
NACairns
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Re: Question: Preferred DOF with reasonable working distance

Post by NACairns »

Interesting topic Kyle and one that I struggle with as well. Lots of helpful comments. As you know Kyle I make regular use of a pringle's can extender/diffuser fill flash and high f-stop (13-22) which is helpful for crispness but I find I still get flares and the colour a bit too warm. The idea of a sunlight diffuser sounds interesting. Is it hand held? Chris do you use a reflector as well to increase the general brightness? I always have trouble getting the natural light to use a small aperture.

ImagePseudacris fouquettei by N Cairns, on Flickr

ImageCharina bottae by N Cairns, on Flickr
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chrish
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Re: Question: Preferred DOF with reasonable working distance

Post by chrish »

NACairns wrote:The idea of a sunlight diffuser sounds interesting. Is it hand held? Chris do you use a reflector as well to increase the general brightness? I always have trouble getting the natural light to use a small aperture.
I sometimes handhold it, I sometimes get someone else to hold it, I have leaned it against a tripod leg or I have put it in a tree/bush before as well. They weigh almost nothing.
I thought about using a reflector in combination, but I only have two hands. I will use a diffused flash as fill if I want some more light.
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Kyle from Carolina
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Re: Question: Preferred DOF with reasonable working distance

Post by Kyle from Carolina »

Wow, the sun diffuser shots look awesome. I would have never thought of that. Seems like a cheap/lightweight technique too, I dig it.

Bill, I'm glad you mentioned the micro 4/3 as an option. I've been looking into that recently after a friend recommended it. I love that those cameras are so compact and they appear to be quite field-friendly.

Nick, I liked that extender/diffuser you had. I've been thinking about making one for myself. You mention the photos being warm, could that be due to the color of the inside of the pringles can? And what do you use as the diffuser material, was it wax paper?
NACairns
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Re: Question: Preferred DOF with reasonable working distance

Post by NACairns »

Hey Kyle,
I'm not sure about the warmness, the pringles can has a silvery reflective layer on the inside but it could be the reflector which is made out of velum. A material that I was not aware of but my wife uses for craft type things and suggested it. Works pretty well even in the rain, an advantage for frogs. I might try a type that is little less transparent as you can see I still get flares.
ImagePseudacris crucifer by N Cairns, on Flickr
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chrish
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Re: Question: Preferred DOF with reasonable working distance

Post by chrish »

Interesting about the pringles snoot/diffuser. Does it extend the range of the flash at all?

Instead of velum, why not just cover the end with the white plastic of a kitchen trashbag? Cheap, waterproof, easy to carry "spares", available at a convenience store.

Actually, while I am thinking about it, why not just use the semitransparent pringles lid as the diffuser on the end.

EDIT - I just watched (no sound) this you tube video of a guy making a diffuser with a pringles can and he also uses a styrofoam bowl to broaden the diffuser and shows some of the diffuser materials you can use on the end (paper, styrofoam sheets, plastic cutting board material, etc).

NACairns
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Re: Question: Preferred DOF with reasonable working distance

Post by NACairns »

Yes it extends the reach of my on camera flash over my 55mm lens (and extender) which allows me to take wider angle "macro" shots without the lens shadow. That said, with the tube, there is a definite tunnel vision effect if the subject is too far away (~2 m). I've tried the plastic bag route but I found it increased this effect. I imagine the original cap would do the same but I cut my tube at an angle in an attempt to direct light down so it wouldn't fit on this iteration. The velum is nice as I use a large rectangle that extends out on either side of the tube and bulges out to further scatter light. It comes in a number of varieties/transparencies and I get 2-4 diffusers per sheet and so far I'm still on my first one even after a tough, wet field season and huge family road trip. I like the idea of a styrofoam plate to expand the scatter. I was going to try to make a new extender for this field season so I may try that.
Best,
Nick
ChadHarrison
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Re: Question: Preferred DOF with reasonable working distance

Post by ChadHarrison »

chrish wrote:
captainjack0000 wrote:Sunny day, ISO 200, f/13 with the sigma 105mm macro, before owning the external flash. I don't like the shadows.
Image
Another solution for this problem is using a diffuser in sunlight.

Here I used a collapsible 30 inch diffuser to create diffuse shade on the snake -

Image

Here's a collapsible 12 diffuser disk for a smaller snake (with fill flash) -

Image

In this case, I used a white snake bag as a diffuser between the sun and the snake -

Image

Here, I simply put the snake in the shade created by the car -

Image
Chris, if you could give me a brand or link to that 30" collapsible diffuser, that would be excellent. I need to add that to my arsenal.
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chrish
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Re: Question: Preferred DOF with reasonable working distance

Post by chrish »

ChadHarrison wrote:
Chris, if you could give me a brand or link to that 30" collapsible diffuser, that would be excellent. I need to add that to my arsenal.
I don't know what brand I have to be honest. I have several of them ranging from 12" to 30".
The small ones will fit in your pocket when folded up, but only work for smaller subjects obviously.

They range in price from < $20 to > $75 online. I suspect a cheap one would be fine!

http://www.amazon.com/s/ref=nb_sb_noss? ... h+diffuser

Actually, this deal looks pretty sweet -

http://www.amazon.com/Neewer-43-inch-Co ... VVYP5V7Y1F
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