Re: APO Germinars etc.
I would be interested in a 750 Germinar, or a little less so for the 600.
Frankly, since practically no long lenses for large format are presently being manufactured now-a-days, I can see the values of all of them rising over time. I believe they are good investment. There willl always be plenty of hobbyists interested in the larger formats and even that interest appears to be growing.
Originally Posted by acroell
Thanks for providing this additional information. I was not aware of the published infinity coverage specs for the longer APO Germinars. These numbers, if accurate, would indicate that:
The 600mm APO Germinar can cover 8x20 with some left over for movements and just hit the corners of 12x20 wide open.
The 750mm APO Germinar can cover 16x20 with movements wide open.
Even with the most conservative specs (46 degree coverage) the 1000mm APO Germinar can cover in excess of 20x24 wide open at infinity.
If the 57 degree number for coverage "stopped down" is realistic, that would yield image circle of 651mm, 814mm and 1085mm for the three lenses. This theoretical data would certainly indicate that these lenses are capable of covering very large formats for general pictorial use.
Additional Disclaimer: Again, as Arne stated above, these calculated image circle values are based on the coverage specs published by Docter Optics and have not been verified by me experimentally.
However, this data is also consistent with the limited feedback I have received directly from users who have actually checked the coverage of these lenses. One user reported that with even with maximum combined front rise and shift on his 12x20 Phillips he could not exceed the coverage of the 750mm APO Germinar. Another report indicated an image circle in excess of 600mm with no mechanical vignetting (at which point his camera ran out of movements) for the 600mm APO Germinar.
So, the only remaining questions are just how far do you need to stop down to get the full 57 degree coverage and what is the optical performance at the outer most edges of the image circle. At some point this becomes entirely academic as most people shooting such large formats are used to stopping down quite far for depth of field issues and most likely contact printing.
To the best of my knowledge, the only non-telephoto large format lenses longer than 480mm being made today are the 600mm Fujinon C and the 550mm and 1100mm Schneider Fine Art XXL lenses. This is actually an increase over what was available a couple years ago when all the longer process lenses had been discontinued and prior to the introduction of the Fine Art XXL series. There are longer telephotos available, but they have much narrower coverage angles than non-telephotos of the same focal lengths.
Originally Posted by Bob Eskridge
It is still possible to find longer lenses, particularly longer Red Dot Artars and APO Ronars, on the used market, but they don't seem to show up on eBay as frequently as they did five years ago when all these lenses were being dumped on eBay due to the transition of the reprographics industry to digital reproduction.
Even shorter lenses covering the ULF formats will continue to be harder to get. Samples of the 355mm G Claron and 450mm Nikkor M still seem to be plentiful and reasonably priced on the used market, but both are out of production. So, there is a fixed supply that will continue to re-circlulate as people enter and exit the ULF market.
Kerry, you can find these numbers on page 51 of my Docter article as part of the text, not in the tables. The basis for these numbers is a photocopy of a hand-typed sheet that came from Docter with some other Docter information, and that is why I put some caveats in the text there. They have never shown up in any other Docter literature. The statement that the numbers are for wide open lenses is my deduction since that list shows higher values for the shuttered versions, where the size 3 shutter limits the open aperture to a smaller value. The 57° is for the 600mm at f/11.5 (650mm), it is 56° for the 750mm at f/14.5 (795mm), and 53° for the 1000mm at f/19.5 (995mm circle). I would take them with a grain of salt, as the same table lists 61° for the smaller focal length (240-450mm), which is quite high for an Artar type.
Thanks for the clarification. I was only looking at the values in the table when I made my post. So, the actual coverage probably lies somewhere between the conservative 46 degree spec and the perhaps "best case" 57 degrees. The 57 degree number may represent the maximum circle of illumination. How much of that is usable is subjective.
As I know of nobody currently shooting with anything larger than 20x24, there is little point in quibbling over the coverage of the 1000mm APO Germinar. It doesn't really matter if it covers 46 degrees, 48 degrees or 53 degrees, the true coverage can be summed up in one word: "enough".
For the 750mm, even if we are fairly conservative, it should cover 16x20 with quite a bit to spare. The real question with the 750 then becomes, can it cover 20x24. It sounds like it's real close and will depend on how far it is stopped down, and what the performance is near the limits of it's coverage.
The 600mm should be usable on formats up to 8x20 and likely 12x20 at typical working apertures. Like the 750mm on 20x24, the 600mm could possibly be usable on 16x20, but again you are approaching the very limits of its coverage at that point.
Of course, all this discussion assumes the lens is focused at infinity. For subjects closer than infinity, coverage increases substantially. Due to the very long focal lengths of these lenses, many users may be technically shooting "close-ups" without even realizing it.
While the 61 degree spec may seem quite high for an Artar type lens, Fuji lists the coverage of their 300mm f8.5 C as 66 degrees. They are a bit more conservative with the 450mm (57 degrees) and 600mm (55 degree) C series lenses. These are also 4 element air-spaced designs based on the classic Celor/Artar design.
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Kerry- I would be interested in either the 600mm or 750mm, price dependent of course. I'm looking at building my own 12x20 portrait camera and that about fits the bill.
Originally Posted by kthalmann
I am interested in 750 or perhaps the 1000 depending on price. Do you know the diameter of the flange? Does it fit within the dimensions of a Sinar size board? Thanks.
I should have pricing info on the longer lenses in the next day or two.
Originally Posted by TheFlyingCamera
Originally Posted by pelerin
Here is the info on the mounting thread diameters for the longer lenses:
600mm = 90mm rear thread diameter
750mm = 110mm rear thread diameter
1000mm = 110mm rear thread diameter
All three lenses will fit on standard Sinar boards and mounting flange rings will be included in price of the lenses.
I would be interested in the Germinar lenses probably in the 150-240 range as well as the 600 assuming it can be mounted in a shutter.
Originally Posted by kthalmann