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New Member
Australia
41 Posts
 Posted 09/12/2019  02:08 am  Show Profile   Bookmark this reply Add Moheb1979 to your friends list Get a Link to this Reply
Sorry another question - what should the setting on the lens be? It has this physical button on the side with 3 options: 0.38-0.53m / 0.53m - infinity / FULL

What are these and what do they mean?
Pillar of the Community
United States
3123 Posts
 Posted 09/12/2019  08:12 am  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
The button adjusts the autofocus range. AF lenses can be easily confused, especially macro lenses which must be able to focus over a very wide range of distances. The settings make it easier by limiting the ranges and thus the lens can't get confused as easily.

However, for coin work you should never use auto focus! I have yet to meet an AF lens which was consistent enough in focusing to trust. Usually they are just a little off in either direction because they focus on a high point or on the field. For coins, you need to focus manually, and perform critical focusing on a middle-height feature.

How have you been focusing your shots? I forgot to ask that important question since I'm so used to manual-only systems.

There should be a M/AF button on the lens as well, and it should be on M.

We can talk further about the process for critical focusing if that is new to you.
Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
New Member
Australia
41 Posts
 Posted 09/12/2019  9:02 pm  Show Profile   Bookmark this reply Add Moheb1979 to your friends list Get a Link to this Reply
Yup, I do manual focusing thankfully, I too never felt that the auto-focus gets it right - I usually look at my computer screen and slowly move the ring both ways till I get it to the best possible focus, however now I'd love to learn what's the "critical focus process"!
Pillar of the Community
United States
3123 Posts
 Posted 09/12/2019  9:42 pm  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
Critical focus is when a middle feature is chosen, and the focal plane adjusted so that the middle feature is in perfect focus, while at the same time the working aperture is selected such that the highest and lowest features are in acceptable focus.

Coins have a wide ranging topography, with each coin type having its own "middle height feature". For example, on the Lincoln Wheat cent, the middle height feature is the middle of the throat between the collar and beard. The highest feature is the jaw joint, and lowest feature is the field just to the right of the throat. You can easily place the zoom window such that all 3 of these features can be seen simultaneously at 100% zoom. By adjusting the focus such that the middle of the throat is in focus, you can then judge if the highest and lowest features are in acceptable focus by moving focus up/down slightly. If they are not, then you should adjust the aperture smaller (larger number) and then re-adjust focus higher and lower until you find an aperture which results in highest and lowest features having acceptable focus. You know you have gone too far when all the feature levels start to get blurry, indicating that the aperture is too small. The goal of the critical focus process is to find the aperture where all the features are in best focus yet are not blurred by too small aperture. Once the working aperture is selected, the aperture should be opened fully, and focus should be made on the middle height feature, then the lens should be stopped-down to the working aperture, and the shot taken.
Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
Pillar of the Community
Canada
4621 Posts
 Posted 09/13/2019  08:57 am  Show Profile   Bookmark this reply Add mcshilling to your friends list Get a Link to this Reply
Ray it is always interesting reading your info and learning more.
New Member
Australia
41 Posts
 Posted 09/13/2019  9:49 pm  Show Profile   Bookmark this reply Add Moheb1979 to your friends list Get a Link to this Reply
OK just started playing with the settings

The attached picture,top row is my old settings, M and standard - the bottom one exact same coin, lighting, focus etc but changed to AV and picture style is now neutral 0,-4,0,0 and -2 EV.

Also old setting was f/7.1 and new is f/10

ISO remains at 100 for both, 1/125 sec speed

No retouching whatsoever in Photoshop aside from cropping, note that I'm still using my old copy stand,new one should arrive in 2 weeks - overall thoughts and comments?

Pillar of the Community
United States
3123 Posts
 Posted 09/13/2019  10:24 pm  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
-2EV is too low. I would not recommend going more than -1. I usually use -2/3 or sometimes even -1/3 if the lighting is very diffuse. What you're looking for is the highlights to be just below full exposure. Your shots above show highlights that are fairly dark. It may still be OK but you may start to lose shadows.

Also, why did you choose F/10? For your Cent shot the magnification is probably around m=0.6, making the effective aperture Feff=10*(1+0.6)=F16. This will probably result in loss of sharpness.

Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
New Member
Australia
41 Posts
 Posted 09/15/2019  01:48 am  Show Profile   Bookmark this reply Add Moheb1979 to your friends list Get a Link to this Reply
So sorry I think I got confused when you said -2/3 I thought you meant -(a full)2 or (a full)3 but I think I understand now that you meant 2 thirds of a full number.

Also I think I need to still practice and understand more the formula, how do you determine magnification? I used f5.6 this time I feel it's better but a little bit flat -
what are your thoughts?

Pillar of the Community
United States
3123 Posts
 Posted 09/16/2019  06:44 am  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
Looks like pretty good "raw material". Now you can adjust the contrast to show the luster a bit better. Are you happy with the sharpness? It looks better to me than your first pics.
Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
Pillar of the Community
Canada
4621 Posts
 Posted 09/16/2019  09:15 am  Show Profile   Bookmark this reply Add mcshilling to your friends list Get a Link to this Reply
Have you tried a different back ground?
New Member
Australia
41 Posts
 Posted 09/16/2019  7:20 pm  Show Profile   Bookmark this reply Add Moheb1979 to your friends list Get a Link to this Reply
Hi Ray, I think it's definitely getting better, I have a few questions still though!
1. OK I'm getting fascinated about the formula, I "guessed" that this should be an f5.6 since its close in size to a US cent, you mentioned that one of the variables was m=magnification, can you elaborate on that? How do you calculate it?

2. Is this raw material photo acceptable by your standards? Do you usually do a slight post processing or should they come out absolutely perfect? I'm assuming you'd edit ithe CR2 raw file not the jpg is that right?

3. Any comments on my lighting and angles? I'm almost always at 10 and 2 with the 150 watt lights.

4. Do you diffuse the lights or are they ok like that?

5. Another question: do you raise your coin on something or just leave it on the copy stand? Its a technique I read about, tried it but couldnt see any obvious advantages so wondering if I'm doing it wrong.

@Mchilling, I usually take the shot on either a thin black cloth or directly on the copy stand - what would you recommend and do you have certain backgrounds for certain metals?
Pillar of the Community
United States
3123 Posts
 Posted 09/16/2019  8:05 pm  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
I'll answer in-line below...Ray

Hi Ray, I think it's definitely getting better, I have a few questions still though!
1. OK I'm getting fascinated about the formula, I "guessed" that this should be an f5.6 since its close in size to a US cent, you mentioned that one of the variables was m=magnification, can you elaborate on that? How do you calculate it?

RP>>Magnification is the ratio of the size of the image on the camera sensor versus the actual object size. I mainly shoot Cents, which are 19mm in diameter. If I fill my T2i sensor, which is 14.8mm tall, with a Cent, the magnification is m = 14.8 / 19 = 0.78 (also expressed as 0.78x, or 0.78:1). I usually don't fill the sensor with the coin, instead leaving about 5% of the sensor free on top and bottom, so that the coin fills 13.3mm out of the 14.8mm sensor. Magnification is then m = 13.3 / 19 = 0.70

2. Is this raw material photo acceptable by your standards? Do you usually do a slight post processing or should they come out absolutely perfect? I'm assuming you'd edit ithe CR2 raw file not the jpg is that right?

RP>>I can't tell you for sure unless I have the full size original file, with no edits. I would need the full size file to look at 100% pixel level detail across the coin to make sure top/bottom/left/right are all in proper focus, and that the pixel-level sharpness is good. I'd also need to review the histogram to make sure there are no crushed shadows or blown highlights, but indeed there don't appear to be. If you are interested I can do a review, just send me an email.

3. Any comments on my lighting and angles? I'm almost always at 10 and 2 with the 150 watt lights.

RP>>The reverse looks pretty good, though I do see highlights on the upper left edges of the devices, indicating that your light at 10:00 is too low an angle from horizontal. The obverse shows this to some extent as well.

4. Do you diffuse the lights or are they ok like that?

RP>>I use Jansjo LEDs (mainly because they run cool and have a convenient gooseneck) which I always diffuse, sometimes extensively. My preference is to use lens-mounted diffusers rather than diffusing the light itself. I can then control the amount of diffusion by varying the distance of the lights from the diffuser.

5. Another question: do you raise your coin on something or just leave it on the copy stand? Its a technique I read about, tried it but couldnt see any obvious advantages so wondering if I'm doing it wrong.

RP>>I place the coin on a velvet "transfer disk". The background comes out a little above black out of camera (with low contrast settings) but is easily pushed to black in post processing.
Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
Edited by rmpsrpms
09/16/2019 8:05 pm
New Member
Australia
41 Posts
 Posted 09/17/2019  01:37 am  Show Profile   Bookmark this reply Add Moheb1979 to your friends list Get a Link to this Reply
Hi Ray!

How can I email you my raw files? They're 25MB each, can you pm me your address please?

Can you show or let me know what kind of lens diffusers you use please? Also same for the transfer disk-is it basically a cylinder thats smaller than the coin or am I getting this wrong? Would love to see your personal setup too!
Pillar of the Community
United States
3123 Posts
 Posted 09/17/2019  10:31 am  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
Moheb1979...I tried sending you my info but you have emails turned off. If you go into your profile and turn emails on, you can send me an email to get things started...Ray
Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
Pillar of the Community
Canada
4621 Posts
 Posted 09/17/2019  1:45 pm  Show Profile   Bookmark this reply Add mcshilling to your friends list Get a Link to this Reply

Quote:
what would you recommend and do you have certain backgrounds for certain metals?


I put a piece of 18% gray paper on the copy stand, it may be just me but I'm not too keen on the black back ground.
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