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Old Jan 22, 2013, 9:24 AM   #11
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That would decrease the focus distance and the DoF too much to be of use.

His subjects are 15-20cm across, which requires at most a 1:6 magnification ratio and a significant DoF (or focus stacking.)

He's doing ok with the gear he's got, but he's at the very limit of what he can do with it. Extension tubes and even close-up lenses would be too much of a change.
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Old Jan 22, 2013, 9:48 AM   #12
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Originally Posted by zig-123 View Post
1- the 18-55mm is actually a good & SHARP lens when used between f8 and f11. but, like all budget lenses, the sweet spot is in the center with the corners a little softer.
In fact, since corner sharpness isn't really an issue for spitfire-303's images, he could even go further. But the smaller aperture, with the resulting larger DoF, is what's letting him get as close to his subjects as he is. Using a larger aperture means a shallower DoF, which means he'll have to increase the subject distance, which will also change the perspective. I think that one of the more attractive aspects of his photos (aside from the exquisite detail of his subjects) is the perspective he's getting. Increasing the subject distance will change that almost as much as a 40mm focal length lens will.

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2- By using a focus stacking software, you can use aperture settings that give best results rather than using extreme apeture settings that while increasing depth of field also have a tendency to show artifacts, dust spots ,oil spots etc. that are found on the lens and sensor on the finished image. some of which you can see on the sample images.
Absolutely, and if he had a lens that had a closer focusing distance than the one he's got (like the Sigma 17-70 I mentioned), then he can use larger apertures and focus stacking while preserving the perspective.
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Old Jan 22, 2013, 10:03 AM   #13
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Absolutely, and if he had a lens that had a closer focusing distance than the one he's got (like the Sigma 17-70 I mentioned), then he can use larger apertures and focus stacking while preserving the perspective.

To your point about the use of another lens, I totally agree that a macro prime is not necessarily needed here. Another lens that, I think, would do a better job than the 18-55mm is the Nikon 18-70mm ED IF DX AF-S lens.
A pre-owned one can be had for less than $200. It is a much sharper choice than the 18-55mm.

By the way, the exif data on one of the sample images states that it was taken at a 24mm focal length. The depth of field, at a distance of 24inches from subject, using an aperture of f16, focal length24mm would yield a depth of field somewhere around 1.32ft.

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Old Jan 22, 2013, 10:29 AM   #14
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To your point about the use of another lens, I totally agree that a macro prime is not necessarily needed here. Another lens that, I think, would do a better job than the 18-55mm is the Nikon 18-70mm ED IF DX AF-S lens. ...

True, but the 18-70 has a minimum focus distance of 38cm, versus 28cm for the 18-55 he's using now.

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By the way, the exif data on one of the sample images states that it was taken at a 24mm focal length. The depth of field, at a distance of 24inches from subject, using an aperture of f16, focal length24mm would yield a depth of field somewhere around 1.32ft.
True, but ...


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... The distance between the camera and the model is around 12-15 cm. ...
... with a subject to focal plane distance of 24cm, the total DoF at f/16 is less than 6cm, which is less than the width of his models. Plus, he can't focus that close (re: mfd of 28cm) without using the DoF that a very small aperture gives him.
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Old Jan 22, 2013, 5:30 PM   #15
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Thank you all for your answers. All are VERY appreciated. I've read everything twice to understand it all. Thanks to Tcav explanations I've performed some test shooting the same picture with 28-40-55mm focal length. I do understand the difference now. In my simple words with 40mm FL I was obliged to put the camera at around 32cm away from the model to be able to capture 100% it and at 55mm it was over 45 cm. I'm not completely sure what I'll do but I'll try to look around me if I can borrow the nikkor AF-S 40mm for a day or two to see what it really does to me.
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Old Jan 22, 2013, 6:28 PM   #16
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If you're in the US of A, you rent one at

http://www.lensrentals.com/rent/niko...-af-s-dx-micro
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Old Jan 22, 2013, 6:46 PM   #17
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At 40mm and a subject distance of 32cm from the lens (44cm from the focal plane), you should be able to use an aperture of f/22 to get enough DoF, which should almost double your shutter speed.

But the big difference will be the perspective. With a wider angle of view and a closer subject distance, the far side of the model is considerably narrower than the near side. With a longer focal length and a longer subject distance, it will appear less like you're standing in front of it.
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Old Jan 22, 2013, 6:50 PM   #18
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I live in France.

Quote:
But the big difference will be the perspective. With a wider angle of view and a closer subject distance, the far side of the model is considerably narrower than the near side.
Sorry I don't get this one. Is it god or bad?
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Old Jan 22, 2013, 9:02 PM   #19
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I traced over your image of the T90. I think it will show what I mean. For your images, I think a shorter focal length give a better perspective. The models appear full size because the perspective is similar to what someone might have while standing next to a full size tank.. (I hope you'll excuse the crudeness.)
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Old Jan 23, 2013, 2:52 PM   #20
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thank you for that explanation and all your efforts. While simulating the 40mm lens I haven't noticed this kind of difference. I will check again the pictures.
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