I have posted this in another forum. I thought some here might be interested. I have been developing my rig so as to be able to take 1-1 Magnification images of Morgan dollar sized coins. Last week at ANA summer seminar I took procession of the key element for my approach to parallax free stitching. ( this technique will allow stacking as well). The item was a Fotodiox Vizelex Rhinocam. The Rhino cam was originally designed to enable a Sony nex to act as a Digital back for a large format Field Camera. It has since been developed to allow APSc and full frame cameras to produce 645 medium format pictures( and large panoramas) I thought It was an ideal piece of kit for making medium format coin images.
Here is Fotodiox's video of how to use the Rhinocam as they designed it:
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Here is my set up using a Mamiya 645 Bellows( with tilt, shift and swing)
From my reading of reviews of the Rhinocam I gained the impression that it would be best used mounted on a medium format bellows. I am currently using a mamiya 645 80mm macro. I am waiting for the arrival of an adapter that will allow me to fit my 105mm Printing nikkor to the bellows. I also have plans to obtain a Hasselblad 120mm macro( medium format) but the cost involved will probably see me buying that lens next year. The Printing Nikkor will only work for coins less than 50 mm in diameter I am hoping it will be ideal for 38-43mm diameter coins.
I have had a few trial runs with the set up using the Mamiya 80mm. There is a steep learning curve as the image size means I have to adjust the exposure for each of the eight pictures that make up the final image. However the work is worth it as the following picture shows. The medal is silver with Matt finish. It is 64 mm in diameter. I couldn't use 1-1 magnification I didn't measure but I estimate the actual magnification was around .8. The picture is just slightly larger than 25 inches on each side and is only 32.8mb.
The medal was illuminated using two E 14 led lights directed through two dffusers made of aluminum honeycomb( visible side-on in the first picture) supported by modelling clay( DAS)
Hi AK...good to see you post here again. Nice image and coin/medal. Looking at it in pixel level detail, it is sharp at the top, but not as sharp at the bottom. Is this due to coverage issue of the lens as a result of the shift function? I assume you stacked the source images so everything should be in best focus. Also, shouldn't the center of the two branches be at the bottom such that "1971 JAMES BERRY" is flat at the bottom of the coin? ...Ray
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I would have to check on the medals composition ie: placement. As for the sharpness.. it was a test shot with no stacking. There is a fault with the Mamiya bellows It has been restored with new 3d printed Shoes/bushes ( the bits that fit over the rail; I have no idea what the proper term would be). These Bushes are the bits that fit tightly over the bellows rail Yet as tight as they are ( I had to sand them to fit) the bellows tilts(sags) towards the front ever so slightly. The parts you identify as soft were actually at the bottom Meaning the medal was photographed upside down. Stacking will sort it..but at the cost of more shots than necessary. It is an issue I am in the process of fixing with two modifications to my rig....I have two thin panorama (rotating) Arca clamps on the way). I could also address it by adjusting tilt on the bellows but for now I am just learning how to operate the Rhinocam on my rig. As my rig has developed and my skills have got better very small mounting differences are translating into very noticeable issues on the photographs. I have a proper trial to process today. 14 stack of the obverse and reverse to process today(total 224 images) It will be a real test of the set up.
the second fix will be replacing the copy stand column and mounting arm. Although it is a Kaiser Copy stand the Camera arm mount( the bit that fits on the column is only friction drive) I believe the "sag",less than a degree, may well be being compounded by that "Cheap" mount It is in the budget next month to replace the column and Mounting arm with a counter weighted Column which also has an Arm locking screw.
This issue only becomes apparent on dollar and larger sized medals. Each time I push the envelop I discover new "faults" with my rig!! RAF camera advised me last night the adapter I need to fit the 105mm Printing Nikkor to the Mamiya Bellows will be in the post today. I fully expect the printing Nikkor to show up more issues that I need to address. I have discovered as Enrico warns in his book that Copy stands are not ideal!
Heres the resultant picture from a total of 224 pictures. It is very much a learning Picture. For the obverse image I ignored Fotodiox's recommendation that when blending the images Vignetting control and Geometric distortion correction be applied. From now on I will follow those instructions ( if you look carefully you will realize why) the reverse picture was with those two corrections turned on, and it is much more life like in appearance. Fotodiox is wrong on what camera settings to use I found its best to use manual. To set the exposure I moved the rhinocam around until the whole sensor was filled with the coin then I set the exposure and did not adjust it again
the lighting was not the ideal type... From previous experience near on axis lighting is best for these shots with the Mamiya 80mm
one more test. This photo is a little frustrating my old eyes "missed" the start of the stacking sequence with the result the fields are not as sharp as they should be. Lighting was problematic. To get the best lighting, although it immediately brings in more softness, I used a Lighting rig modeled on a Siemens DOAL( Diffuse on Axis lighting) unit. The lens added some limitations as the short focal distance of the Mamiya 80mm did not allow me to place the coin optimally( lens would have collided with the beam splitter). All indications so far suggest that the set up should sing with the Lens I developed it for ( printing Nikkor 105mm). With the nikkor I will use a microscope ring light not the beam splitter. With the nikkor I will be using almost all of the image circle the lens produces so I do wonder if I am going to see some previously unreported artifacts( vignetting, peripheral distortion etc) From my experiences with that lens so far I doubt it....but you never know until you try.
Here is the photo ( there is heaps of room for improvement especially note the coloration of the lower part of the medal)
What really intriques me is that in the past when I have tried stitching I have obtained 100mp + images. With this technique I am only getting 40mp plus but with much higher visual quality. That suggests, to me, that the technique is much more efficient I do wonder how it might compare in comparison to a telecentric lens. I went in this direction because I wasn't confident with a telecentric set up
austrokiwi wow great images. a question you say this is almost identical to the coin. I like that you have done and excellent job on your coins. so you do this by stacking. what does that mean are you taking many picture and then putting them together some how. I am just wondering if you don't mind my asking.
With that photo there was no stacking, Only stitching was used. Magnification is 1-1, lens was a medium format Mamiya sekkor c 80mm set at F8. At F8 the depth of field made stacking unnecessary. All I did was take the eight photos needed to create a 645 sized image and then used the panorama stitching program in Adobe elements...... there was one other major contributor....I installed a graphics card to the computer; the processing speed and the quality of the output was significantly better( a note..... the picture looks heaps better on my screen I have no idea what it looks like on others). That sort of photo really makes me wish I had the cash for a medium format camera!! The 80mm isn't the sharpest of lenses so I am waiting for the arrival of the adapter( next week I hope) that will allow me to use the printing Nikkor. One observation The Rhinocam was designed for outdoors use... the amount of set up time I have to go through to photograph a coin suggests to me that it not that useful for its claimed design purpose. As RMPSRMPS observed the Rhino cam is an X-Y shift adapter. One thing I forgot to mention to fit my camera on the Rhinocam( in portrait orientation for the 645 format) I had to use an extension ring set, which actually made setting the 1-1 magnification simpler
austrokiwi thank you. great info and really great photos. I am going to read and study this a bite. I am going to try this. like your results I will see later what I can do. again thank you
Rocky the only issue is price the Rhinocam for the nikon mount is expensive. Actually I think a cheap Sony Nex ( manufacturer refurbished) would do a very good job with the Rhinocam ( my A7r is over kill in this case) Last picture until I get the adapter:
Coin is a Birmingham mint 1780 Maria Theresa thaler trial strike in Copper, most probably struck in 1949 ( only 8 struck) edit I don't recommend clicking on the image and down loading it, as admin pointed out in another forum, its a 68MB download of 162 Megapixel stitched image! No wonder I needed to add ram and a graphics card There is some softness in the image..either I missed the focus with my old eyes or I need to get a new Column for my copy stand( probably a combination of the two)
hello austrokiwi well tried my first stack using adoble photoshop elements 13. it was of a 2006 twoonie. it went very well. I was quit surprised by the size of the image. once I cropped it and down sized it. I must say it went well. I will do a bunch more before I start to post any yet. wanted to ask you your e14 lights is it this one, 2015 Bright 15W Energy Saving E14 69LED in the shape of a light bulb day light variety. I was wondering or is yours the one shaped like a flat light square panel with 72 bulbs. I seen one that was flat and it came with a diffuser, light colour was 5000k with diffusion just wondering. watched the rinocam video quit a piece of gear. have a great one
For the last shots I was using a beam splitter( edmunds 50/50). The lighting for it is a 160 led light panel of 5600k. The beam splitter is mounted in a set up I modeled on a Siemens DOAL 75 unit ( obviously mine is larger than the Siemens unit). The siemens unit uses 6000 k lighting. For other lighting I use 12 watt LED E14 lights( 15 would be better). For long exposure shots.... I use two self made spotlights( using minolta 55mm 1.8 lenses to control the beam and dim the light) these are also powered by E 14 LED lights
Surplus Shed occasionally has good deals on interesting stuff. Right now (ending today...) they are offering a Computar LF 105-150mm zoom lens for $20. Quite a deal. Not sure how to mount it but should not be too hard. Here is the link:
I ordered one but I am not holding out for a great lens.... Zooms have never done well with me and coins. I did a quick google search a couple of sites mentioned that it could be a medium format enlarger lens( zoom variety). That site has been selling them for years at US$20.00 ( plus postage its worth a punt) Edit... I wrote to soon....they apparently were designed to fit a twin lens reflex camera so the mount is going to be a bit of a challenge
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Posted 07/05/2015 6:15 pm
There is some softness in the image..either I missed the focus with my old eyes or I need to get a new Column for my copy stand( probably a combination of the two)
