Macro Test Page
The basic test...
For all the photos the Oly C-750 was used and no cropping was done so that you can correctly judge the magnification and the amount of the frame that was filled. These were all taken as HQ 2288x1712 and then resampled to 800x600.
The native C750 supermacro mode test...
Note: The native C750 supermacro mode does not seem to gain any advantage from the Nikon 4T. It does not provide any visible magnification of the photo. I do not bother with including photos of this.
Now I will proceed with the C750 in normal mode with the full 10x zoom (380mm equivalent).
The C750 at 10x with Nikon 4T (2.9 diopter) test...
The native supermacro mode DOF test @ F3.2...
The native supermacro mode DOF test @ F8...
The C750 10x Nikon 4T DOF test @ F3.7...
The C750 10x Nikon 4T DOF test @ F8...
This is the 75mm-12.5mm C-mount video camera lens...
For this test the lens is being hand held up against a UV filter so the quality will be somewhat questionable. I thought I had a reversing ring for this lens but I don't have the correct size (49mm?) The working distance is a inch or less and the DOF is difficult to work with.
The C750 at 10x with 75mm reversed C-mount camera lens test...
The C750 at 10x with 50mm reversed C-mount camera lens test...
The C750 at 10x with 30mm reversed C-mount camera lens test...
The C750 at 10x with 12.5mm reversed C-mount camera lens test... poor results because this is very difficult...
Conclusions:
Native C750 supermacro mode will focus 1.2 inches to approx. infinity.
C750 with Nikon 4T has a focussing range of approx. 9 to 12 inches with C750 at 10x with a broader range if zoomed out.
C750 Normal mode has a focussing range down to approx. 3-4 feet at 10x but will focus as close as 2.8 inches when fully zoomed out.
The Nikon 4T macro lens (a dual element 2.9 diopter lens) provides a nice comfortable working distance but also a very shallow DOF at 10x and only a slight magnification advantage. This might be most useful when you cannot approach the subject as closely as the native supermacro mode would require.
The reversed zoom lens provides only an inch or less of working distance and an extremely shallow DOF. The reversed lens obviously produces a high magnification. I believe a 50mm reversed lens is supposed to be roughly 20 diopters. I would suggest that a reversed lens might only be comfortable to use if you also had some sort of geared focussing rail to support the camera and set the distance with. The images at 12.5mm were poor and almost impossible to take handheld.
Questions:
Without using a macro lens what is the exact trade off between zooming out so you can focus closer or zooming in but needing to retreat to a greater distance so as to be able to focus?
Do the dual-element macro lenses really have improved CA and edge sharpness over the less expensive single element types?
Would stacked dual-element diopter macro lenses provide good results?
Would the larger diameter of a 35mm SLR lens eliminate the vignetting?
What type of adjustable focussing rail could be used to stabilize a macro shot?
Other links of interest...
[http://www.photoblink.com/info.asp?Article=articles/bugPics.xml]
[http://homepages.ihug.com.au/~parsog/photo/macro1.html]
[http://www.digitalstar.com/Bigmouse/]
[http://www.stevesforums.com/phpBB2/viewtopic.php?t=15584]
[http://forums.dpreview.com/forums/read.asp?forum=1008&message=7083233]
[http://www.imagestation.com/album/?id=4287433283&code=8827793&mode=invite&cmp=EMC-IS_other&creative=album_invite]
[http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/Odd-Stuff/Reversed-Nikkor/reverse-closeup.html]
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