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rmpsrpms

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  1. The differences are noticeable even at the smaller image size, but any one image in isolation looks "OK". If you compare a larger image the differences are more obvious, but for publishing on the web at 800x800 pixels any of the lenses can do an OK job.
  2. I did a shootout/comparison of 75mm lenses a while back (see here: http://www.coincommunity.com/forum/topic.asp?TOPIC_ID=98494&SearchTerms=75mm). I chose 75mm because it is just long enough to make work with most bellows on Dollar size coins, and short enough to keep the setups compact. It is my preferred size for use on the small microscope stand setups I favor. But some folks prefer larger setups, and some bellows have minimum extensions that are too long to work with Dollars. Both these situations require longer lenses. I am an avid El-Cheapo enthusiast, and have watched eBay for deals
  3. That's correct. All done with software. It would be extremely tough to get this level of clarity with a tilted coin. The stack depths would be excessive and the result would likely not be very good.
  4. The process is the same as focus stacking, ie taking a series of photos at different focus planes and then using software to create a composite image using only the in-focus parts. There are several software packages that will do this such as Zerene Stacker, Helicon Focus, even Photoshop. The software creates a "depth map" as it moves through the stack of images, so it knows the relative depth of the in-focus parts it includes in the final image, and can then use this depth map to create variable-angle perspective representations of the image.
  5. Here's a 1949-S Lincoln Cent DDO#3 presented with a couple of techniques. Unprocessed image using 5x magnification, 25-stack of images: Unprocessed image using 10x magnification, 36-stack of images: 3D processed 10x image but looking straight on to compare with unprocessed: 3D processed 10x image looking at 45-deg from 9:00: 3D processed 10x image looking at 45-deg from 2:00 I think this technique is useful to help visualize these kind of variety details in a similar way to viewing then with a microscope, at least the way I view them. I'm not so sure the 3D versions of the
  6. I haven't posted here for a while so I thought I'd post something a bit different... I've been searching for a long time for a nice quality example of this famous Nikon 4x objective. As Mark Goodman states in his review, "this lens is the standard by which all others are compared in this magnification range". You can read Mark's review at: http://coinimaging.com/nikon_4apo.html As a test of this objective I took a picture of a 1955-S RPM#1 from a group of 7 I found in a recent roll search. The objective performed every bit as well as expected. Here is the image: Note that this image
  7. I've had good luck with microscope slides for axial lighting of cents. I take a small piece of rigid black foam and cut a 45-deg angle in it, then tape the slide to the foam. You need to make sure you put a non-reflective black surface behind the reflector to avoid having it re-reflect up to the sensor...Ray
  8. I've read different accounts on stacking order but I've never tried testing it to see if it really mattered with CZP. Certainly with two images it won't matter, but not sure about 3 or more. First image in the sequence is taken as the reference, and all others are resized / shifted x / shifted y / rotated versus that one to line up critical features identified by the software. I've recently thought it might be best to have the image that has critical focus on the most important feature you are trying to show be the reference to keep it from suffering sharpness loss due to resizing, but have no
  9. Sorry, I don't think I have any coins about with higher relief. Most of what I own are relatively modern US coins, all of which have fairly low relief. Bigger coins have higher relief but require less magnification, so on a % basis they are about the same. The only change that happens with higher relief is that more individual shots are required as part of the stack to get all planes in critical focus. I'll look around and see if I have anything appropriate...Ray
  10. When you take photos at higher magnification, depth of field becomes a problem. With film cameras you pretty much needed to stop-down the lens until you got a reasonable DOF, and hoped that happened before diffraction caused the image to get too soft. But with digital cameras you can keep the aperture open, and adjust the focus a little at a time up or down to get a sequence of shots where each plane of the image is in focus. For coins at around 4x magnification, this is usually 3-5 shots. Then you can "stack" those together using a "focus stacking" program like Helicon or Zerene (or CZP, whic
  11. I know what you mean about the variability using different viewers. Some of my images are stacked using CombineZP. The source images look better in CZP than in any other viewer I have used. No idea why. All my editing is done with Nikon ViewNX/NX2 and it seems to be fairly balanced in presentation. I usually check the images using Firefox as the viewer before posting to the web, figuring that many people use it or some other similar web browser that all have similar jpg viewing engines. By the way, the ISO for the above images was 100, so that's also not a factor. I am actually learn
  12. This image was slightly sharpened ("1") after downsizing it to 800x800. In my case the "specklies" are due to the LED lights being very small point sources. They go away if you diffuse the lights a bit...Ray PS I just looked back and realized I posted this coin twice...sorry
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