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 Replies: 25 / Views: 4,232 |
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Pillar of the Community
 2087 Posts |
Quote:
Since you're using backlighting, have you considered reflective frontlighting? If you put a reflector just beyond the lens, you can have the backlight reflect off it and light the coin. I've done it with two LED lights very successfully in the past. Just a thought... I wish I had an A77 mine is the a65..... I think the A77 would be more adjustable...but the sensor is the same size so I think you comment still applies( am I correct?) As for reflector...I tried that with the 50mm and hadn't thought of repeating it with the sigma. To make the reflector I just took some aluminum foil crumpled it then smoothed it out and shaped it like dome. I gotta give that ago!! Edit: I tried a few different techniques nothing matches the second photo I posted. I think the big issue at the moment is, apart from inexperience, I do not have adequate lighting and the tripod shakes too much. In the next couple of weeks I will construct a proper axial lighting rig...and If I am successful with a current ebay bid will convert a Minolta color enlarger ( has a really solid base and vertical, as opposed to angled, riser) to a copy stand and then I will have another go( also with better lighting) I appear to have ironed out the issues with back lighting. On the back lighting I tried some axial lighting ( just by supporting the beam splitter glass with some books). However 50 % of the back light is now reflected away.... so the background ends up with a bluish tinge........So its also off to get an 18% grey card to custom set the WB. It fun but the endless tweaking can be annoying. That said manual set up is heaps more effective than using the auto settings Edited by austrokiwi
07/23/2013 04:32 am
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New Member
United States
41 Posts |
You can get a wired remote shutter release for about $10 at B&H. This is a must. You should focus manually and use your smart telephoto button in the magnification mode for very sharp focus!
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Pillar of the Community
2087 Posts |
You can get a wired remote shutter release for about $10 at B&H. This is a must. You should focus manually and use your smart telephoto button in the magnification mode for very sharp focus!
Exactly...... I have had a remote( wired) shutter release for some time now..and that telephoto button works a charm. The other thing I do is switch off the cameras image stabilization system
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Pillar of the Community
2087 Posts |
Now I have sorted out a copy stand its back to learning how to photograph. I had been using a 1600s coin but its fields were uneven and I couldn't tell at times if it was my photography or actually the coin so I switched to a modern coin: New Zealand 1955 3 pence. I picked an un-circulated example with good fields. This following shot was at F8(if I up loaded the right picture. No back lighting and using ambient light( just in case I used the wrong word: day light) Any constructive criticism( please ignore the dirt in the background) is greatly appreciated as I am sure the only limitation with this lens is me.  |
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Pillar of the Community
United States
627 Posts |
I think improved lighting would improve the sharpness of the images (by decreasing the exposure time). At least, just as a casual "outsider looking in" the images look blurry to my eye. Do you have an IKEA nearby in Austria? Many of us here in the states have had very good luck with these little lamps: http://www.ikea.com/at/de/catalog/p...ts/50163202/ |
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Pillar of the Community
2087 Posts |
thanks I hadn't thought of IKEA will head over there later in the week...with that last shot I think I may have left image stabilization on( not good because it will compensate for movement when its not there).
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Pillar of the Community
2087 Posts |
BRG5658. Thanks for the comments now its dark in my part of the world I tried again this time with a ring light and back lighting.I also turned the room lights off. Image stabilization was also turned off Its definitely getting there ( perhaps wearing my reading glasses helped with focusing as well!!)  |
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Pillar of the Community
United States
627 Posts |
That definitely looks better. I can't say enough good things about those little IKEA lights though. It's like they are specifically make for numismatic photography needs. You won't regret picking up a few (I use 3) when you see what they do for your images. I think your work on the enlarger to make it into a super sturdy copy stand is amazing! It looks like it's rock solid now. And, as for the new image, it's definitely sharper (and by the way, I really like that little gem of a coin!).  |
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Moderator
 United States
23522 Posts |
Yeah, you're getting what you deserve from your equipment now.  I like the way the lighting pictures this coin. However, as brg mentions, point-source lighting like the little Ikeas have their own advantages in certain circumstances - I think they'd better illustrate luster at the cost of less-even lighting over the entire surface. I'd recommend them as an alternative setup. For instance, although I'd cheerfully offer technical grade opinions based on the image here, I'd be less-inclined to factor luster into the final details of the grade. Try a lustrous piece of silver to see what I mean. |
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Pillar of the Community
2087 Posts |
Finally got to Ikea. those little lights are brilliant. For now I just purchase two. LED lighting is so directional that for now I thought I would try just with the two tonight when its dark I will try the rig with the two lights on a proof coin.
LOL I couldn't resist and I tried. I am not posting the photos as they were terrible. We recently renovated and where I have the copy stand is very bright with day light and all the walls are white painted as a result the ambient day light is a huge compounding factor. I will try tonight when I can get better control....newt I will be looking for a black out tent(Joke)
Edited by austrokiwi
08/09/2013 07:10 am
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Moderator
United States
23522 Posts |
Not so much a joke - I do not shoot during daylight. Ever.
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Pillar of the Community
2087 Posts |
I can see why you don't shoot in daylight. Here is my next try. A nice shiny 1946 NZ 3d. I think I could do better with a little more time spent on setting up the shot. The lighting was 2 IKEA Led lights, as was recommended earlier in the thread( I will be buying two more I think). I used an LED back light and most importantly I custom set the white balance using an 18% grey card.....the photo represents the coins color more accurately than I have ever achieved before. I didn't use my reading glasses so I suspect the focus may be a little off:  |
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Pillar of the Community
2087 Posts |
Today I sorted out an axial lighting rig( using beam splitting glass) SO tonight I tried it out with this lens. First off it is obvious I need more lighting ( to get the following shot I had to set the ISO to 3200). The coin used as the "model" is an Ethiopian Matt proof birr. Although the background looks bluish the coin is in "real life" color. Apart from more lighting any other suggestions?  |
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Pillar of the Community
United States
4038 Posts |
WOW, quite a coin!
Axial setups are tough to get to work well since you by definition lose 2 stops of light through the two beamsplitting actions. You just need to get more lights in there, or get the light closer to the glass, etc. I highly suggest using the mirror technique to align your lights for maximum illumination on the coin. Just put a mirror where the coin is, and then adjust your light angles and position so that its reflection is just slightly larger than the coin and centered over the sensor. This will minimize the light reflecting off the surface the coin is sitting on and maximize the light hitting the coin. You also need to make sure no direct light is hitting the coin, and that any light passing through the beamsplitter is absorbed by a black absorber. Any of that first light that reflects back to the beamsplitter will reflect off the beamsplitter and go directly to the lens, thereby messing with your black levels and contrast.
Looking at the image itself, it seems the sharpness is not fully there. I don't know if this is lack of critical focus, or diffraction rearing its ugly head, or a combo.
I also like to remind folks of the 3 rules for a good photograph:
1) Composition
2) Focus
3) Exposure
I bring these up because you're not quite there on #1...you need to rotate the coin a few degrees CCW. The ground that the lion is standing on should be flat...
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
2087 Posts |
Quote:
Looking at the image itself, it seems the sharpness is not fully there. MMMM may be that coin wasn't a good choice. It may well be that the coin might be a little out of focus, I had taken shots of the 46 3d and they weren't great( had some fluff in the background. So I went for a dollar sized subject. It is possible the "sharpness" isn't there because of the coins treatment. What I mean is that photo apart from the "composition" really captures the coin as it is in real life. The actual surface of the coin is "Blurred". As a matt proof: after the die surfaces were polished they were washed with acid producing a uniform graininess over the die surface. There are no "sharp" lines on that coin. I'll try again tonight( We must buy blinds for that room( just newly made; the rebuild only finished a couple of weeks ago) with the 46 3d. Edited by austrokiwi
08/13/2013 04:01 am
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Posted 07/25/2013 7:19 pm
