Hi everyone
please look at the two insect pics I took and give me some advice
I took the fly using a tamron 70-300mm macro and 3 kenko extension tubes..I seem to be having trouble with getting the whole of the fly in focus..what am i doing wrong ?
the ladybird was taken with a Nikon 50mm 1.8D and the large kenko extension tube and I found the same problem..getting the whole ladybird in focus
http://mysite.orange.co.uk/daveputty/index.html
Help & Advice needed
Moderators: rjlittlefield, ChrisR, Chris S., Pau
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dave_putty
- Posts: 43
- Joined: Wed Nov 08, 2006 9:26 am
- Location: sheffield
Help & Advice needed
Nikon D80
Hi Dave! I'm short in time so just a few words for now. I still do not use adapters and extension tubes so maybe I'm not a right person for giving advice. But generally speaking you are dealing with phenomenon called "DOF". I'm sure our "macro geek" members would give you more detaild explanation. Meanwhile, maybe you'll find this link helpful. 
The meaning of beauty is in sharing with others.
P.S.
Noticing of my "a" and "the" and other grammar
errors are welcome.
P.S.
Noticing of my "a" and "the" and other grammar
errors are welcome.
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rjlittlefield
- Site Admin
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- Location: Richland, Washington State, USA
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Dave,
Hi -- surely I'm one of the "macro geeks" that MacroLuv referred to.
Yep, you've run into DOF (depth of field). Shallow DOF at high magnifications is a fundamental problem that nobody in the world has figured out how to solve. It has roots all the way back to the fact that the wavelength of light is really pretty long. But let's not go there now.
Your lady beetle looks typical. There's sharp detail in a shallow slab, centered on the point of best focus and parallel to the sensor plane. Moving forwards or backwards from that slab, things get progressively more blurred.
Your fly shows this same effect, and in addition it's blurred from subject or camera motion.
For a beginner, the key thing to know is that one can get more DOF by stopping down the lens (using a smaller aperture). To keep a usable exposure time, more light may be needed. Electronic flash works well because it cuts motion blur too.
It's also important to know that DOF only depends on a couple of things: 1) total magnification, and 2) how big the aperture appears to be (angular dimension), from the standpoint of the subject. Given the same magnification and the same apparent aperture size, DOF does not depend on focal length, sensor size, extension tubes, close-up lenses, teleconverters, etc etc. Buying more equipment in search of more DOF is generally a waste of time and money.
It's also important to know that there's a strict limit on how much DOF you can get in a single shot. Beyond a certain point, stopping down your lens just makes the whole picture fuzzy due to diffraction. (That's where the wavelength of light matters.) See this article for some illustrations of just how fuzzy things can get at, say, f/45 with a 1" subject.
Again, your lady beetle looks typical. You can probably get some more DOF by stopping down, but you're never going to get the whole beetle crystal clear in a single shot. In fact, for a 5 mm subject displayed at 150mm wide (total magnification 30X), the formulas in this article indicate that maximum DOF is only about 1/3 mm. (That maximum DOF also happens at a surprisingly wide aperture -- around f/8 with your equipment. Below that, diffraction kicks in.)
Look through the galleries to see how other people are handling limited DOF. The usual approach is to decide what parts of the critter you care most about (often the eyes), focus on those, and just accept that other parts will be blurred.
Hope this helps,
--Rik
Hi -- surely I'm one of the "macro geeks" that MacroLuv referred to.
Yep, you've run into DOF (depth of field). Shallow DOF at high magnifications is a fundamental problem that nobody in the world has figured out how to solve. It has roots all the way back to the fact that the wavelength of light is really pretty long. But let's not go there now.
Your lady beetle looks typical. There's sharp detail in a shallow slab, centered on the point of best focus and parallel to the sensor plane. Moving forwards or backwards from that slab, things get progressively more blurred.
Your fly shows this same effect, and in addition it's blurred from subject or camera motion.
For a beginner, the key thing to know is that one can get more DOF by stopping down the lens (using a smaller aperture). To keep a usable exposure time, more light may be needed. Electronic flash works well because it cuts motion blur too.
It's also important to know that DOF only depends on a couple of things: 1) total magnification, and 2) how big the aperture appears to be (angular dimension), from the standpoint of the subject. Given the same magnification and the same apparent aperture size, DOF does not depend on focal length, sensor size, extension tubes, close-up lenses, teleconverters, etc etc. Buying more equipment in search of more DOF is generally a waste of time and money.
It's also important to know that there's a strict limit on how much DOF you can get in a single shot. Beyond a certain point, stopping down your lens just makes the whole picture fuzzy due to diffraction. (That's where the wavelength of light matters.) See this article for some illustrations of just how fuzzy things can get at, say, f/45 with a 1" subject.
Again, your lady beetle looks typical. You can probably get some more DOF by stopping down, but you're never going to get the whole beetle crystal clear in a single shot. In fact, for a 5 mm subject displayed at 150mm wide (total magnification 30X), the formulas in this article indicate that maximum DOF is only about 1/3 mm. (That maximum DOF also happens at a surprisingly wide aperture -- around f/8 with your equipment. Below that, diffraction kicks in.)
Look through the galleries to see how other people are handling limited DOF. The usual approach is to decide what parts of the critter you care most about (often the eyes), focus on those, and just accept that other parts will be blurred.
Hope this helps,
--Rik
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dave_putty
- Posts: 43
- Joined: Wed Nov 08, 2006 9:26 am
- Location: sheffield
DOF
Wow yes thank you for your help...I was so frustrated today testing my new D80 and kenko tubes...I thought it was a fault...but now I know what your talking about...I have been doing little tests with stopping down and shutter speed
Also thank you Macroluv It is so nice to listen to your english "P.S.
Noticing of my "a" and "the" and other grammar
errors are welcome". you remind me of my girlfriend who is from Russia it's wonderful how you sound...dont change anything
Also thank you Macroluv It is so nice to listen to your english "P.S.
Noticing of my "a" and "the" and other grammar
errors are welcome". you remind me of my girlfriend who is from Russia it's wonderful how you sound...dont change anything
Nikon D80
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dave_putty
- Posts: 43
- Joined: Wed Nov 08, 2006 9:26 am
- Location: sheffield
ref DOF
Do you guys think I should use a software prog such as HeliconFocus or is that cheating? I have seen some awesome macro pics on this site and would love to achieve this
Nikon D80
Re: DOF
You are welcome Dave. Sounds as I'm commedian here.dave_putty wrote:... Also thank you Macroluv It is so nice to listen to your english "P.S.
Noticing of my "a" and "the" and other grammar
errors are welcome". you remind me of my girlfriend who is from Russia it's wonderful how you sound...dont change anything
In love and macro anything is allowed.dave_putty wrote:Do you guys think I should use a software prog such as HeliconFocus or is that cheating? I have seen some awesome macro pics on this site and would love to achieve this
HeliconFocus works just fine for static subjects. 
The meaning of beauty is in sharing with others.
P.S.
Noticing of my "a" and "the" and other grammar
errors are welcome.
P.S.
Noticing of my "a" and "the" and other grammar
errors are welcome.
-
rjlittlefield
- Site Admin
- Posts: 24150
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
Re: ref DOF
Some of us are ardent believers in "stacking" -- a general term for what Helicon Focus and a few other programs do to achieve extended depth of field.dave_putty wrote:Do you guys think I should use a software prog such as HeliconFocus or is that cheating? I have seen some awesome macro pics on this site and would love to achieve this
Helicon Focus is excellent -- go for it!
--Rik