| Author |
 Replies: 25 / Views: 4,229 |
|
Pillar of the Community
2087 Posts |
Following the advice I received at the ANA summer seminar. I purchased a 105mm macro lens. The advice was that 100 mm was the best particularly with smaller sized coins. My main Macro was a Sony 50mm macro which was ok for Thaler/Crown sized coins but with smaller coins the coin image would only fill half the available field. The new lens I purchased second hand( at least my wife did) from Adorama in New York the "New" lens is a Sigma EX 105mm macro for Minolta/Sony A mount. I had been a little nervous as some of the older Sigma lenses have compatibility issues with the Sony A65 and A77 cameras. The main reported issue is that AF does not operate. Not having AF was a problem I could happily live with hence My wife picked the lens up for me last week. It arrived today when she returned from New york. Although I still have to sort out a decent lighting rig I was impressed with the first shots I took. A pleasant surprise was that the AF works fine. Here is one shot( you can see the lighting was too bright.) The "new" old lens is a step up from 55mm. Note: the picture has been reduced by 90% so that it could be posted:  Edited by austrokiwi
07/21/2013 04:26 am
|
|
|
|
Pillar of the Community
 United States
4038 Posts |
Your lighting looks fine but the pic is too small to judge anything about the lens. If you want to send me a larger image (up to 10MB) I'll host it and we can all see how well your new lens is doing! Click on my user name, and on "Send an email".
|
|
Pillar of the Community
United States
4038 Posts |
austrokiwi...I got your email with large jpg and uploaded to Photobucket. PB downsizes the image when posting but you can always follow the link to my PB gallery and view the full-size file. The downsized file is big enough to start making comments. I'll reserve my comments until we hear from others on the forum...Ray  Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
|
Moderator
United States
23522 Posts |
The only comment I'll make right now - have to leave for work in a few minutes - is that it's time you took advantage of a Personal Gallery, another CCF perk you may be unaware of: http://www.coincommunity.org/gallery/It'll allow you to save and post images up to 800x800 pixels, plenty large enough for grading purposes. Drop a quick request thread in the Support Forum and Bobby will hook you up. |
|
Pillar of the Community
United States
9792 Posts |
Very nice, the Sigma macro lenses are quite good quality, I've used the 185mm macro a friend has for insect shooting, works well, sharp and crisp.
"Buy the Book Before You Buy the Coin" - Aaron R. Feldman - "And read it" - Me 2013! ANA Life Member #3288 in good standing since 1981, ANS, Early American Coppers Member (EAC), Colonial Coin Collectors Club member (C4), Conder Token Collector Club member (CTCC), Civil War Token Society (CWTS) member, Liberty Seated Collectors Club (LSCC) & Numismatic Bibliomania Society member (NBS), USMex, Member in good standing, 2¢ variety collector. See my want page: http://goccf.com/t/140440 |
|
Pillar of the Community
 2087 Posts |
Thanks for the comment any critiquing is greatly welcome. I wasn't happy with that photo I tried a few more times. This next one (same coin for comparison was taken at F16 with a 1.3 second exposure. Its sharper....but I still don't think its good enough. I think the major problem is the tripod it just can't keep the camera still enough. While setting the photo up I could see by the movement on the LCD screen level that there was still some shake going on( A copy stand is what I am hunting for at the moment) The F value used is higher than what online reviews suggest is sharpest for this lens. The coin was photographed on a LCD back light and was elevated using a small pedestal. Thanks for the example of Photo bucket I used it for this image:  Edited by austrokiwi
07/22/2013 06:07 am
|
|
Moderator
United States
23522 Posts |
You want to be able to shoot between 1/100 & 1/200 (depending on luster) at f/8. Maybe down to 1/60 for dull coins. That will help immeasurably with sharpness, which your lens should have in spades. If this is unreachable, brighter lighting is in order.
|
|
Pillar of the Community
2087 Posts |
Thanks for that tried it at F8 But with the lighting the exposure was best at 1/50th. Also tried F6.3 at 1/60th. Unfortunately its daytime and I was getting too much extraneous external light...so I'll wait til tonight aand try then and post the results at F8. From this current trial F8 certainly seems to have much more potential
|
|
Pillar of the Community
United States
4038 Posts |
Your second pic looks much better. How big is the coin? Going from f/16 to f/8 will likely be a significant improvement.
I'm curious about your backlighting...I've never had good luck with it and am wondering why you use it?
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
|
Pillar of the Community
2087 Posts |
Quote:
How big is the coin? The coin is 22 mm in diameter Quote:
I'm curious about your backlighting...I've never had good luck with it and am wondering why you use it? I use it so that I have an even white background..it helps in editing...and if I don't want to cut out the background I can just do a square crop. The big problem with the back lighting, for me, is getting light "bleeding" over the edge of the coin. (You can see that most obviously in the first picture. Elevating the coin helps. |
|
Pillar of the Community
United States
4038 Posts |
Your A77 has pixel pitch of 3.9um, so the DLA is around f6.2. Shooting at f16, your effective aperture is about f26, around 4x the DLA, so you can get away with a 4x downsizing without much loss of detail, but a 2x downsize or especially 100% will look quite blurry.
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...
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
|
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
|
|
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!
|
|
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
|
|
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.  |
|
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/ |
| |
Replies: 25 / Views: 4,229 |
Posted 07/21/2013 3:17 pm
