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 Replies: 24 / Views: 3,446 |
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Pillar of the Community
 United States
4038 Posts |
The problem with higher pixel count in a fixed sensor size is the pixels get smaller and smaller. This leads to extreme limitations of aperture vs diffraction. I use a Canon T2i, which has 4.3um pixels, and a diffraction limit of f6. The D3200 has 4um pixels so diffraction limit is around f5.6. So you can only take advantage of the camera at high mag if you can keep an EFFECTIVE aperture of f5.6 or larger (smaller number). So let's talk Dollars...
For DX sensor with ~16mm height, magnification to fill the screen is 0.42. So you need a lens with aperture setting of 5.6/1.42=3.92, or f4. At this aperture, DOF will be relatively poor.
So what about letting the lower magnification work for you? Let's calculate filling the sensor only by half, so M=0.21: 5.6/1.21=4.7. DOF will improve with lower magnification and smaller aperture, but this is only a half-stop smaller, and you are losing bigtime in being able to average-out those pixels to improve sharpness in the final image. You are effectively using a 18x12mm, 6MP portion of the sensor!
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Pillar of the Community
United States
1620 Posts |
ummmm is that english lol
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Pillar of the Community
United States
1620 Posts |
i need a disposable camera
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Pillar of the Community
 United States
1151 Posts |
First picture, any suggestions?   |
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Rest in Peace
United States
10625 Posts |
Congrats yankee. You are one step ahead of me. My Canon P&S crapped out and I'm looking to purchase a new Canon. Problem is I keep spending my camera budget on coins.
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Pillar of the Community
United States
1620 Posts |
i just changed the mp from 14 to 3 and the picture quality is way better is there a program I can use to improve the photos I'm new at picture taking
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Moderator
United States
16679 Posts |
Not bad Billy. I'm still trying to figure out where the pink came from. I always shoot against a black cloth background (in my case a knit cotton glove) with indoor incandescent lighting. I use the super-macro setting @ 1600 on the 500UZ. Always take the coins out of any holder excusing any slabbed coins of course.
swcoin.ecrater.com
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Pillar of the Community
United States
1620 Posts |
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Pillar of the Community
United States
1151 Posts |
Getting better..  |
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Moderator
United States
23522 Posts |
Nice. The bottom looks a tad out of focus compared to the top, indicating you're not as parallel lens-coin as you could be. That's one thing to look for. Second, consider the actual size of the images you're getting, and how you might crop the image to show only the coin. That will make it easier to post larger coin pics without running afoul of whatever size/space limitations might exist wherever you upload it.
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Pillar of the Community
United States
1151 Posts |
Quote:
Nice. The bottom looks a tad out of focus compared to the top, indicating you're not as parallel lens-coin as you could be. That's one thing to look for. Second, consider the actual size of the images you're getting, and how you might crop the image to show only the coin. That will make it easier to post larger coin pics without running afoul of whatever size/space limitations might exist wherever you upload it.
So be more steady? Do you mean crop it when I use the image optimizer? |
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Pillar of the Community
Canada
4944 Posts |
You should use a tripod, and make sure the camera is set at 90 degrees to the coin. For the best images.
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Valued Member
United States
402 Posts |
Let me get in on this. Are you saying that if I reduce the megapixels from 6 say down to about 2 I may get a sharper better coin image. Also how about the quality. I use very fine mostly, should I reduce that down also.
edgman
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Pillar of the Community
921 Posts |
Proper lighting & a tripod are most important. Natural sunlight makes things alot easier too...Use a timer on the camera to avoid shakes. Read your cameras manual for the best settings to use on your camera for this. I took this picture today with my Canon T3i(18mp)using a Canon 100mm lens from about 3 feet away without the tripod. It was a full sized picture of 4 Canadian silver dollars in the binder, but I cropped it down quite a bit using my picture editor due to the size restrictions...  |
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Moderator
United States
23522 Posts |
Quote:
Are you saying that if I reduce the megapixels from 6 say down to about 2 I may get a sharper better coin image. Also how about the quality. I use very fine mostly, should I reduce that down also. No, quite the opposite. Always use the largest, finest picture settings. "Cropping" an image is to remove anything which isn't coin from the image, usually done by drawing a square around the periphery of the coin and deleting everything else. That gives you the largest-possible image in whatever size restriction you face when you upload and post. Downsizing a larger image tends to sharpen it anyway. |
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First Page
Posted 09/11/2012 4:42 pm
