Hi all - have a Nikon D80 with a 105mm macro lens that I like to take photos of insects with. My problem is narrow depth of field means that I will for example have the insect's wing in focus and the eye out of focus.
I cannot figure out the best setting to maximize depth of field with the flash. There has to be some optimal combination of aperture, shutter speed, whatever, that increases my depth of field when using the flash. Or put another way, how can I use the built-in flash to maximize depth of field?
#1. "RE: How to maximize depth of field" In response to Reply # 0
Welcome to Nikonians Thom.
I would think that if you're shooting in the 1:1 reproduction range that the built in flash would be of minimal use. Reason being is that the working distance at that reproduction range would mean the lens might cast a shadow on the subject. For macro shooting off camera flash is a big plus. Many people find a ring flash benificial or the expensive Nikon R1. I have successfully used a single SB800 off camera though. Depends on your shooting circumstances and needs.
As to DOF, it's entirely dependent upon aperture and subject distance. To increas DOF with macro imaging there is only two choices; multi-frame focus stacking and plain old cranking down the aperture. Focus stacking is more suited to static subjects, cranking down the aperture is subject to diffraction. Personally I crank down the aperture and accept a small loss in fine detail which I feel is offset by the gain in DOF.
#2. "RE: How to maximize depth of field" In response to Reply # 0
Depth of field is governed by three things: focal length of the lens, distance to subject and aperture. Aperture is the one variable that your on-camera flash can potentially help with. Potentially, because as was noted, a lens (especially one the size of the 105) can cast a shadow in some circumstances. This does not seem to be the case with the AF Micro 105mm 2.8D on the D90. I gave the light a little advantage by using a Gary Fong Puffer to act as a diffuser (it robs about 1 stop) but also to move the illumination source about an inch forward along the lens.
I've posted two shots of a single Black-eyed Susan bloom taken from one setup on a tripod with the lens at nearly maximum extension - it's within about 1/10 inch of subject to sensor minimum distance - the best I could do with grippy tripod feet on a rough floor. I'm looking at the bloom as I write this: the greeny center measures about 3/8" (9 mm) across and is, roughly, a hemisphere. The thicket of stamens, etc add about 1/8" (3mm) to the radius. The whole assembly is about 5/8" (16mm) across. They project about 1/4" (6.5 mm) from the petals.
I only focussed once, before the first exposure. The first is 1/200, f8, iso 160, flash (manual, 1/16 power). The second is 1/200, f57, iso 400, flash (manual, full power) - this had to have its exposure increased by 1/3 stop to bring the histograms within spitting distance. The difference in perceived detail is substantial, whether you like the quality of the detail or not.
Except for the one exposure adjustment, downsampling and identical export sharpening both images are out of camera. So, the short answer vis-a-vis the on-camera flash would seem to be Yes. Thanks for provoking me to do the experiment. I'll admit to being surprised, perhaps even delighted.
#4. "RE: How to maximize depth of field" In response to Reply # 3
Agreed. But then you are restricted to essentially a 2-D representation of the beast. One needs to take more heroic measures to render a 3/4 image in detail, which seemed to be the gist of the OP's post. BTW, your photo works for me, too. In a big way. Congrats.
#5. "RE: How to maximize depth of field" In response to Reply # 0
I'm no macro expert, but you might try intentionally, not filling the frame. The extra subject distance might get you a bit more DOF, then crop the photo for desired image size. Have also used a ringlight for some serious small apertures, however the diffraction is an issue.
#6. "RE: How to maximize depth of field" In response to Reply # 5 Sun 08-Jul-12 12:08 PM by elec164
> not filling the frame. The extra subject distance might get you a >bit more DOF, then crop the photo for desired image size.
Unfortunately that doesn't work as you suggest. DOF is an illusion based upon the limited acuity of human vision. It's dependent upon the amount of enlargement of the capture and the viewing distance of the observer. Yes not filling the fame by increasing the focus distance will gain some DOF. But cropping then enlarging negates the gain creating a wash at that point.
>Have also used a ringlight for some serious small apertures, >however the diffraction is an issue.
Yes diffraction is real, but in my opinion often over stated and fretted about. Also by using deconvolution the affects of diffraction can be mitigated. For example look at Hendrik's examples. If you look at the narrow DOF example you can see where the plane of focus is with no diffraction affects (assuming that's a full frame capture). Now look at the same area in the wider DOF capture. Yeah there is a small loss of fine detail, but with proper PP sharpening that loss will be transparent to the viewer unless its a known subject that the views could mental compare to. That's why when I'm shooting macros, I'm willing to accept a small loss due to diffraction because the gain in DOF adds more to the image than the usually undetectable loss of fine detail.
#8. "RE: How to maximize depth of field" In response to Reply # 0
OK, one more go-round. I took the D90, 105 Micro AF-D and Gary Fong Puffer out on the dog walk (around a multi-acre meadow) this morning to field-test the proposal with whatever I could grab before I had to figure out where the dog had got to this time. I think it could work with a great deal less wind and more patience than I brought to the exercise. The insects were most uncooperative, skedaddling before I was anywhere near focus distance. Again I pre-set the focus of the 105 Micro to just the merest fraction of a turn before full extension (just short of 1:1). Focussing was accomplished with my legs and back muscles. The most patient bugs were grounded from wind. That made focussing and tripping the shutter too much like a video game for my taste. The two best exposures I was able to make involved still leaves in the shrubbery at the meadow's edge. Both were shot at 1/200, f40, iso 320, pop up flash (manual, full). Again, no crop, no PP other than LR's defaults, downsampling and the addition of LR's standard screen sharpening.
BTW, I make no claims for my abilities in this vein - it's not where my interests lie but, rather, I am intrigued by the question of reasonable flash enhancement while traveling light, hence the experiments. With practice it should be possible to learn to judge the correct plane to put the viewfinder focus on to achieve a reasonable DOF that extends from the nearest part of the beetle's wing cover to the tip of its far leg.
I think the real discovery involves the Puffer which eases the shadows and highlights immensely and helps avoid the harsh, flat look. Of course, at this scale, the position and size of the flash approximates an immense soft box positioned well above the camera at normal portrait distance. I made a few exposures of more static subjects (berries) which would definitely have benefitted from a tripod but indicate that the Puffer may actually be more valuable in this wise than the use for which it is marketed.
#10. "RE: How to maximize depth of field" In response to Reply # 8 Sun 09-Dec-12 03:36 AM by mkbee1
At macro distances: small apertures..F/16,22,32 if you got 'em!
Late to this discusion...newbie and all...90% of my macro shots are hand held, most with flash.
I use either the camera hot shoe or a Stroboframe bracket to raise my flash above the subject, and the bounce/swivel capability to point the flash directly at it. Then I use a bounce card or StoFen diffuser to soften the light a bit.
Either way, the flash is raised above the lens' axis, eliminating much chance of the shadow falling on the subject.
Ittl all the way, SC28 cord for the bracket or hand held off-camera work.
Would I love to have the macro goody I see the folks on CSI using? O my yes, but till I win the lottery, or am discovered to be the "long-lost cousin" my "field expedient" solution works just fine.
Diffraction...Yes, it's there, but is not a real-world problem. Bryan Peterson shows excellent examples of the real difference between mid and small apertures in his book, "Understanding Exposure". It's one of the best comparisons I have seen.