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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 on various lenses for a long while (see here: http://www.coincommunity.com/forum/topic.asp?TOPIC_ID=102384). I also have picked up other more expensive but interesting lenses along the way. Many are in the range of 100mm so I decided it would be good to compare them. Keeping in the 86mm-110mm range, I have 22 lenses to compare. I did not include the 95mm or 105mm Printing-Nikkors although I may add them later. The lenses included in this shootout range from 86mm to 110mm; from Japan, Germany, France, and Russia; from enlarging, duplication, and macro applications; and from $15 to $250 on the used market. Many are seen regularly on eBay, while others come around only infrequently. The list includes, in order of increasing focal length: 86mm f5.6 Tomioka E36C duplication lens (fixed-aperture) 86mm f4 Tomioka E36 duplication lens 89mm f5 Rodenstock Scitex S-2 duplication lens 90mm f4.5 Perfex Anastigmat enlarging lens 90mm f4.5 Wollensak Enlarging Raptar enlarging lens 90mm f4.5 Elgeet Colorstigmat enlarging lens 90mm f4 Tomioka E36 duplication lens 90mm f6.3 Perfex Anastigmat enlarging lens 90mm f4.5 Roussel Trylor enlarging lens 90mm f4.5 Lens Made In Japan (no brand) enlarging lens 94.1mm f4 Tomioka E66 duplication lens 100mm f4.5 Lomo Mikroplanar macro lens 100mm f4.5 Kodak Enlarging Ektar enlarging lens 101mm f4.5 Wollensak Enlarging Raptar enlarging lens 105mm f4.5 Vivitar enlarging lens 105mm f4.5 Tomioka Tominon macro lens 105mm f5.6 Rodenstock Rodagon enlarging lens 105mm f5.6 Nikon EL-Nikkor enlarging lens 108mm f5.6 Rodenstock LFOV duplication lens (fixed aperture) 110mm f4 Industar N-100-Y enlarging lens 110mm f5.6 Rodenstock Scitex S-2 duplication lens 110mm f5 Rodenstock Scitex S-3 duplication lens (fixed aperture) I used a 1954-S Lincoln Cent as subject for the shootout. I took overall photos using each lens, with white balance set for Tungsten, so that the color presentation differences of the lenses can be seen. No sharpening was done in-camera or in post-processing. Levels were adjusted equally on all images. Lighting was kept constant for all shots. Of course the lighting will appear different for different focal lengths due to perspective changes, but only slightly within this narrow range. Aperture was held constant at f5.6, or at either the minimum aperture (eg f6.3 for Perfex) or at the fixed aperture of the lens (eg f5.0 on Scitex). This is a wider aperture than I used for the 75mm shootout, where I chose f8. The wider aperture exposes more issues for each lens, and allows a better comparison. The f8 in 75mm shootout somewhat equalized the lens performance, while f5.6 will show more of the differences. In some cases f5.6 is the maximum aperture, while in others it is stopped-down by 1 stop. Critical focus was performed on the middle portion of Lincoln's neck. This is approx in the middle of the topography of a Lincoln Cent, so focusing here gives best balance of focus between fields and tops of the devices. I cropped the center and bottom edge of each shot. The center is over the Neck area where critical focus was done. Bottom edge shows two effects: lens coverage; and field flatness. I only considered out to the edge of the coin, since that's how these lenses would be used, so "corner" sharpness is not really relevant for coin photography. I used my HRT2i, APS-C, 18MP camera for these tests. A full-frame camera would be more revealing for edge sharpness issues, but most coin photographers will likely use APS-C. Now the catch...you need to visit my website to see the images and results! Take a look at: http://www.macrocoins.com/100mm-lens-shootout.html
  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 these is all that useful, but some may like them. I find them kind of gimmicky, and while they can be sort of cool they don't offer any more information than the 2-D perspective views above. If you disagree, let me know. It's not too hard to include 3D versions of these. Ray
  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 is better, but not tremendously better than what can be achieved with a 0.13NA or even 0.10NA objective. Its higher NA (0.2) makes it sharper, but it also means more shots are required for the stack. The image above required 31 shots!! A 0.1NA objective would require half or fewer shots, but each one would be a little less sharp due to the smaller aperture causing diffraction.
  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 not tested that yet. The best images I've seen of coins have lots of images in the stack (often 30 or more). Many folks use a sliding focus rail called StackShot which has a linear stepper motor capable of very small step sizes, and run many shots. I adjust focus manually so can't achieve the extreme resolution and regular step size of a mechanical system like StackShot, so tend to make my stacks based on focusing particular features of the stack in the individual shots. This minimizes the number of shots but may result in a worse stacked image. I am not sure either way since I don't own a StackShot...Ray
  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, which is what I use, and it's free). This technique will allow you to keep maximum sharpness and contrast by avoiding diffraction effects. Interesting thing about this technique is that you can then use microscope objectives on the bellows. A 4x NA=0.1 Achromat costs only US$25-$30 and gives very good results. Single images from such a "lens" will have poor depth of field since the aperture is so wide and not adjustable. But the sequence of images can be "stacked" to stitch all the in-focus parts of the image together. Another interesting aspect is that you don't need to be as careful about focusing. Get as close as you can with the equipment, then move up or down until you are definitely out of focus, and start the sequence. Then move down (or up) in steps, taking shots at each step, until you pass through the best focus point. Then continue until you are definitely out of focus on the other side. Download the images, and look through them to find the first and last shot that has some part of the image in perfect focus. Delete all the rest that show nothing in focus. Then stack them with the program. In my view, this technique brings the best of all available technologies, both modern and retro, to bear on the image-making process: - Digital camera to capture and process the images quickly (modern) - Bellows to allow fine adjustability of magnification and focus (retro) - Highest quality microscope optics to give best sharpness and contrast (retro technology with modern optical standards) - Software to combine in-focus parts of the images together (modern) Now, if you absolutely MUST use film, you can still do stacking but you will need to scan the images first and then use the stacking program on the digital images. Probably won't give quite the same final quality but will still likely be better than stopping-down for depth of field and accepting the degradation from diffraction. Here is a recent stack I did using a $25 4x / 0.1 objective on my Vivitar bellows, with Canon T2i. First three are the images to stack. Notice the field is in focus on the first one; the mintmark on second; and the tops of the digits of the date on the third. The composite shows all in focus.
  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 learning to like those "sparklies"...knowing where they come from and why helps a lot and they add to the local contrast and luster presentation.
  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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