I have time as the Mitutoyo adapter plate I ordered is still in Russia, dancing with customs clearance for almost two weeks. The formula quoted by ADi is a good one.Īfter a little shipping delay my new MicroMate arrived from China today, yay! I'll be investigating and learning how to use it in the coming days, hopefully it won't take me weeks. In this regime, it works well to use formulas based on the NA = "numerical aperture" of the objective. Diffraction determines how quickly the image becomes blurred as it goes out of focus, and it does that so strongly that all other factors can be ignored. By the time you're using a microscope objective, diffraction is the main controlling factor. These formulas work well at low magnifications, say from landscape to close-up photography.īut at higher magnifications, a wave property of light called "diffraction" becomes important. (2) inserting a specific value for "circle of confusion", that reflects typical situations. (1) pretending that blur is entirely determined by ray tracing, ignoring the wave properties of light, and (2) how much blur can be tolerated by the viewer of the image.Ĭlassic formulas like DOF = 2*C*N*(m+1)/m^2 incorporate these two factors by (1) how quickly the image becomes blurred as it goes out of focus, and In general, DOF is determined by two very different factors: I've been studying DOF for 50 years, and writing about it for more than 10, and I have never figured out how to explain it thoroughly yet concisely. You have my sympathy about the difficulty of good references. Thanks in advance for your guidance and expertise! What aperture should the tube lens be set at, does it matter? Can I shift magnification on the tube lens by rotating the focus ring from one extreme to another? Will moving the focus ring impact the quality of the images being captured? How does having a microscope objective combined with the 200mm tube lens play in the formulas that calculate DoF?īeyond Depth of Field, I'm also wondering about a few other things. Nikon Nikkor Micro 200mm f/4 ED-IF, used as tube lens Over time I'll more than likely add similar objectives with 2x, 5x and 20x magnifications. Soon I'll be acquiring a Mitutoyo M Plan APO 10x objective. I'm hopeful that someone can help me figure out how much overlap I'll need between images to increase stacking success. While I wait for the adapter ring to arrive I've been trying to find a resource that would help me understand and calculate DoF for various combinations I'm envisioning. Recently I purchased an adapter ring to mount Mitutoyo objectives to the front. I have a Nikon Nikkor Micro 200mm f/4 ED-IF and will be using it as my tube lens. With the cards I would recommend you go with a trustworthy source as there have been more than a few reports of cards that were counterfeit being sold on e-bay.I have a few questions and concerns about Depth of Field (DoF) calculations for my soon to be real setup. I would trust any of them with major purchases. I have had no problems purchasing over the Internet from Beach, B&H, Cameta, J&R, and Abes of Maine. I have also seen numerous reports from people on this form who really like Transcend cards, so I think I will seriously consider them in the future if the price difference is anywhere close to what you have described. Every once in a while SanDisk has an exceptionally good rebate and they become a real bargain. All I have ever used is a SanDisk MicroMate that came free with a SDHC card I bought, but it has always done the job (though I confess most times I connect the camera and use the EOS program).Īs for cards, I have only used SanDisk (both CF and SDHC) for many years dating back to my Canon S45 and have yet to have a problem of any kind. Omar's suggested reader looks pretty useful.
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