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View Full Version : Wollensak EXWA 6" f/12.5 Image circle

xiaubauu
17-Jan-2011, 04:11
What is the image circle for this particular lens? It's uncoated.

Dan Fromm
17-Jan-2011, 05:37
See http://www.cameraeccentric.com/html/info/wollensak_15.html . Claims 100 degrees.

xiaubauu
17-Jan-2011, 17:54
Thanks. Sorry for my ignorance, but 100degree of a 6 1/4 inch is ehhhh, how big in mm?

Jan Pedersen
17-Jan-2011, 18:17
379mm (aproximately)

xiaubauu
17-Jan-2011, 19:55
Can you teach me how to calculate?

Jan Pedersen
17-Jan-2011, 20:07

ic-racer
17-Jan-2011, 21:35
Image circle radius is the base of a right-triangle with a height equal to the focal length and so the tangent of half the angle of view is equal to one-half the image circle divided by the focal length.

Vaughn
18-Jan-2011, 08:28
I have one, but it does not cover 8x10 well at all. Even closed down all the way the corners on 8x10 are soft and dark. Might just be my lens because others seem to not generate the same complaints. I am going to use it on my 5x7 where I think it will shine.

Vaughn

Michael Graves
18-Jan-2011, 08:34
I have the f9.5 version. Are there any significant differences between the two?

Chauncey Walden
18-Jan-2011, 08:44
My f/12.5 covers 8x10 just fine stopped down.

xiaubauu
18-Jan-2011, 21:54
My f/12.5 covers 8x10 just fine stopped down.

Does it allow for movement?

Chauncey Walden
18-Jan-2011, 22:38
I've only used back movements and it certainly doesn't take much to make a difference. The hyperfocal distance at f/32 would only be 12 feet so 6 feet to infinity is easy to deal with. At infinity only 93 degrees of the 100 degree coverage is used so there should be a little wiggle room left.

xiaubauu
19-Jan-2011, 00:38
that's good. Should be a cheap lens to do Architecture shots then. Thanks.

Robbie Shymanski
19-Jan-2011, 07:25
I can get a couple inches of rise on mine with no problem. Granted, it does need to be stopped down at the extremes.

John Kasaian
19-Jan-2011, 07:32
I have the f9.5 version. Are there any significant differences between the two?

IIRC the f/12.5 has a skosh more wiggle room while the f/9.5 is a tad brighter for focusing. I've got the f/9.5 version.

John Kasaian
19-Jan-2011, 07:43
that's good. Should be a cheap lens to do Architecture shots then. Thanks.

True they currently don't cost a lot but they are also small and lightwieght. By comparison, a 165mm Super Angulon is a mammoth piece of glass and will tax the front standards of any wooden camera. The trade-off is between coverage and speed(the SA wins this hands down) and economy and size (the Wolly wins this one) If your architecture shots require lots of movments, a Wolly will run out of coverage but for shots which don't require much movement the Wolly is every bit the equal (other than speed)

Scott Davis
19-Jan-2011, 07:54
I use the f12.5 version on my 5x12 with no problems. There is some movement with it, not tons, but enough for the 5x12, on which I seldom use a lot of rise. Mine is WoCoated with the purple dot and the WC logo.

Jan Pedersen
19-Jan-2011, 08:03
I like these lenses so much that i have two of them, one is a coated f9.5 Raptar and the other is a coated yellow dot EXWA 12.5
As John mention, the 12.5 does have a very slight edge in coverage. I can get at least 1" rise without any softness in the corners and more without darkenened corners. I do contact printing only.

xiaubauu
20-Jan-2011, 20:41
Thanks. This has been very helpful.

Jim Galli
20-Jan-2011, 22:15
379mm (aproximately)

I measured one on a sheet of 11X14 paper in the camera one time and got 386mm which is close enough to concur with Jan's number. 380 - ish. diagonal on 8X10 is 310 so that leaves 35mm every direction to roam around in.