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 Replies: 10 / Views: 1,949 |
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Pillar of the Community
United States
3076 Posts |
Most of us are trying to find the cheapest way to get a good shot of coins, AND specifically if you are here, your not shoot the zoo animals in the early morning or late at night...I say this because all lenses have qualities and issues....Mostly for the most of us, a general lens, or a point ans shoot camera will fulfill any ones needs, but if your reading this you are in the coin realm, where things are different..... I am posting this because many of you like me look for a lens to take good photo's, and see many ebay and other articles about lenses, but forget to research the quality or usage of the lenses potential or in many circumstances there faults ...... on the cheap side.....we want to pay nothing for a good lens...so we buy it, where does it perform.....ITS BEST? This is a little publisized knowledge unless you research your particular lens and reviews....This info tells you where your lens works its best....and for the lens its best working performance environment, for all color distortion ect. for the use you want to make of it... The thing is,,,,All lenses have there strong and weak side depending on your usage of these cheap lenses, of which I have great results, within my needs... unless you have the money for the top of the line lenses, one should review the lenses you have or are looking for, so they will make the best of photo's for your specific need...For me, after some months reading these many posts of coin photography, I had not considered the true range of the lens to my desired result..and needs...And what we have to work with....It's some thing Super Dave and Ray have been showing us in all of there threads....Knowing the lenses best capability range you have for your own purposes will limit your trials and errors, |
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Pillar of the Community
 United States
4038 Posts |
A word of caution, though...until you get your technique where you can get an in-focus, well-composed, well-lit, and color-correct shot, even the best lenses won't look much different from the poor ones.
I've recently done some "shootouts" that I published on this forum where I tested a wide range of lenses of similar focal lengths, changing only the lens and holding all other parameters as identical as possible (lighting, coin placement, magnification, etc). I did NOT white balance between lenses so that the reader could see what changes each lens imparted on the color. These differences would go away if each lens was individually white balanced, and then they would look even more similar. I should point out that I did not push each lens to its limits, and in all cases kept the aperture closed down enough to eliminate each lens' major aberrations.
What I think these shootouts show is that for a fixed setup, the effect of the lens is relatively small WHEN PUBLISHING AN 800x800 IMAGE ON THE WEB. Starting from a 3200x3200 full-size image, that's a 16X reduction and many of the problems that each lens imparts upon the image get smoothed-over through the reduction process, greatly reducing the differentiation.
The real differences between the lenses start to show up when you look more closely at the fine details in the image. But even here, with the method I used keeping the aperture relatively small, many of the differences are smoothed-over by diffraction effects. Yet using a wider aperture can cause problems with depth of field, and may force draconian measures such as image stacking to get a final image that is superior to the stopped-down single image.
So ultimately you need to decide how much work you want to put in to achieving the very best image possible. If you are only looking to take pictures suitable for Web publishing, then the shootout proves that even a very inexpensive lens (some of the ones I included go for $15 or less) can give acceptable, even very good, results.
If you're looking to get the very best possible, and are willing to go through great lengths to achieve this, then the shootout results are not completely applicable. If you are simultaneously looking for a low-cost solution, then you want to go with a lens that has the following qualities:
- Wide maximum aperture such as F2.8. Few lenses are good at f2.8, but a wide maximum aperture generally means the lens aberrations can be minimized at a larger aperture than one whose starting point is smaller. What I mean is that an f2.8 lens stopped-down to f5.6 is very likely sharper than an otherwise similar f4 lens stopped-down to f5.6.
- Flat field. This is less important if you plan to stack since stacking can partially compensate field flatness issues. But if you don't stack, you need flat field.
- Low chromatic aberration. I use the focusing color-shift test to check this. If at full magnification the color of the coin stays constant when defocusing close or far, you have a winner
Now what lenses meet the above criteria? That will need to wait for a later post. It's dinner time...Ray
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Pillar of the Community
 United States
3076 Posts |
Thanks Ray, I do see your point, as coin photography is such a narrow fixed scenerio...it does not apply to most of all photography..So the main points of close up Macro fixed images photography, Very much different from taking flower pic's and such... All lenses have there strong and weak points
depending on what you want to get out of the lens. or the overall abilliteies from its close up's to full zoom ....
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Pillar of the Community
United States
870 Posts |
Yeah, I'd say generally speaking unless you're buying absolute trash, the limits of the photographer outweigh the limits of the lenses.
There are some really poor lenses on cameras, but even so, most of those issues become apparent in the corners. The center 70-80% of the field (generally what is used to for coin photography) should be just fine. =)
At least... that's my experience.
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Pillar of the Community
United States
4038 Posts |
Yep, coins, being round flat discs, are pretty much the ideal subject for photography. Lens aberrations are equal all around, and as long as you can keep the coin flat the DOF issues are minimized. In my shootouts I included a relatively poor quality Russian enlarging lens (not ALL Russian lenses are poor, in fact some are excellent) as well as Printing-Nikkor, which is hands-down the best 1:1 macro lens around. Here are the images of same coin, same white balance. Lighting is a tiny bit different but as close as I could keep them the same. You can definitely see the difference between these but the differences between lenses at Web sizing is still smaller than the tiny differences in lighting between the shots...Ray Industar ($25 lens)  Printing-Nikkor ($2500 lens)  Contact me for photographic equipment or visit my home page at: http://macrocoins.comEdited by rmpsrpms
11/12/2011 1:40 pm
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Moderator
United States
23522 Posts |
The Nikkor just makes me slobber. Some day....
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Pillar of the Community
United States
3076 Posts |
Got a question, perhaps its the way its being connected?
my camera is the Canon EOS T1i which comes with an 18mm to 55mm lens and gives full shots of Morgans from a slight distance where one has to zoom in and crop to size...
However I recently bought an EOS adapeter to mount my older Ashasi 55mm lens to the newer camera...the lens is a fixed 55mm where the 18-55mm has some variables,
my question is why can't this get full Morgan shots?
attached to the camera,,,smaller coins would not be a problem...with a bellows, its still about the same field of focus, best for smaller coins....how ever I haven't tried it from 2-6 feet, like the 135 may take...any ideas...thanks Gene
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Pillar of the Community
United States
4038 Posts |
Not sure what you mean by "can't get full Morgan shots", please explain further. Certainly the coin does not over-fill the sensor when lens attached to the camera, right? So you should be able to focus at some distance where you see the entire coin and crop like you would the 18-55. Only way this would not be true is if the EOS adapter has a long extension. Anyway, please explain...Ray
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Pillar of the Community
United States
3076 Posts |
Thanks for the reply Ray, My question is perhaps a 2 part question, as when using a variable lens, say like my stock 18mm to 55mm canon lens, NO problem....and when I bought the adapter to put my EL-Omeagar on My EOS, it I could not get it to focus, I then got an adapter to fit my ASAHI 55MM to an EOS and still couldn't get it to focus with attached to the camera...I could see the whole coin, just couldn't get it into focus.. it was like I needed the lens closer to the camera. not the camera closer to the coin....Fixed lens,,,as this is can be a variable..when I attached the same lens to the bellows, its an extreme magnification..no way to get the whole coin in the shot...my 2 part question is this, and for those who read and try to plug A into Z and figure the outcome...these are fixed lenses...so the focal point is at some specific distance.. when attached to the camera it was intended for its a no brainer...distance from lense to sensor and, Voulla...nice pic...add the adapter, perhaps its a might to far, as when using the extention tubes, where you have to play with the tubes combinations to get in the right focus range...in stead of a bellows, where you have some kind of dial in adjustability...
Mind you at this point my only intention is to shoot the coin in macro,, and I haven't tried to shoot across the room which most likely work fine..one thing I have noticed so far using the bellows, is that the lens must be very close to the body,, to focus...instead of at the extreme of the bellows adjustments.. say 6 or 7 inches away from the camera body...This is one area I have to work with...the flexibility of distance of the lens to the camera body using the bellows ====and focus distance from the extended lens from the body to the object.. when the lens is farther away from the body... in simple terms...have any lens on a bellows and extend it to its farthest point from the camera...at that point...how far from the lens will objects come into focus...is it like some you need 3 feet of more when your totally extended?:
I did read your other responce
about the 50mm for full size dollars..., I am just wondering why the stock lens can do it while our fixed 55 don't seam to do it...
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Pillar of the Community
United States
4038 Posts |
55mm is a pretty short lens and needs to be close to the sensor for focusing at infinity. It does not take a lot of movement away from the sensor to focus on a Dollar full screen. The farther you move the lens from the sensor, the closer the coin must get to the lens to be in focus. Can your fixed 55 focus at infinity? If so, you should be able to focus on the Dollar...Ray
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Pillar of the Community
United States
3076 Posts |
Ray I haven't tried it at infinity, as the lens for macro is f something low say 1.8 I saw the whole coin but couldn't get it into focus, no matter what I did, however I did not think to go to infinity...In the middle of moving so I have little time to play with it...it's an interesting thought though.... Thanks for the  Idea. when I get the chance I will try it out....  |
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Replies: 10 / Views: 1,949 |
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Posted 11/07/2011 01:23 am
