Lenses coverage for 16x20

[edward_chung]

Just brought 2 lenses and have no idea whether it would cover my 16x20

with movement. There are: 265mm 1:18 Protar, 370mm F7.7 Collinear.

[light-zone]

Have you tried mounting them and finding out? I can't find them on any lists...

[daniele_tanto1]

The Protar 265 mm. f18 is stated from a Zeiss catalogue from 1931 to cover 10x12 with a circle covered at small stops of 26 3/4 inches (680 mm.) The Collinear series III n.7 (370 mm.) will cover at f32 16x18 inches, this data came from a Voigtlander catalogue of around 1905. The 16x20 inches format (40x50 cm.) has a diagonal of 65 cm. so in my opinion you will barely cover with both lenses even if you must test the fall of sharpness at the corners.

As always tests on fields will help you.

Let me know

Daniele Tanto

[edward_chung]

The only information I got in hand is from the Zeiss Lens book that listed the 265mm Protar lens will cover 9.5x11.75" at F18 and 10.25x13.75" at F36 also there is a Chinese web page http://www.greenviewclub.com/Chat/CameraManual/Protar/Protar.htm marked the lens had a image circule of 680mm. But from the Wisner page the 275mm will cover 20x24". My 16x20 hasn't arrived yet. But to my experience that my 210mm F18 Protar can cover my 8x10 very well but it couldn't cover 11x14 with movement. So I guess the 265mm is only for 11x14 with movement. But for sure that my 480mm F18 Protar will cover 16x20. Thanks, Edward

[clinton_buhler]

16x20? Ha , you guys are freaks! Why would anyone want that much film in their camera? I'd say go 11x14 maybe if your nuts. 8x10 if your half nuts. Here's a question for you. The larger format you go, the further your lens is away from the film. So the more optical spreading will occur. Now at what size will you start to loose image quality by icreasing film size any more? I think it will be by 11x14". I bet you'd get a better photo with 11x14" film than with anything bigger. There is just to much other uncontrollables that are going to actually degrade quality. (i.e. lens softness at corners, and optical spreading/ refrction) I don't think there are any superb quality lenses made that will cover 16x20". Why do you want this format? I'm intrigued though for sure. Much dedication. Clint

[edward_chung]

The reason why for a 16x20? First, I don't believe any enlargement will have better quality than contact print. Second, I am doing platinum print and this is the only way that I can do it in 16x20 format. As far as I know, there are many super lenses that will cover this format. The Zeiss Protar Series V with F18 - 460mm, 632mm, 947mm, , Dagor F7.7 - 480mm, 620mm, 1000mm, Zeiss Protarlinse 970mm+970mm, Voigtlander Collinear/ Kollinear Series II F6.3 - 440mm 520mm, 600mm, will all cover 16x20 inch very well with sharp corners and image.

[metairie_christophe1]

i bought 1 month ago a ZEISS APOCHROMAT TESSAR 640 , wich has an image circle of 48inch ( 121 cm )wide open !!!! a lens like this one covers 16*20 and even 20*24 with room for movements , i'll mount it on a sinar lens board and test the lens next month on my 16*20 camera ...

 

chrostophe - france .