Komura Commercial 300mm f/6.3 in Copal 3

[Steve Goldstein]

Is anyone familiar with this lens, which doesn't appear in the sole Komura brochure on the Camera Eccentric site? I believe it's actually in a Copal 3S, the old style marked simply as "Copal - No. 3" and with the nonlinear aperture progression. It takes 72mm filters, 75mm front, 60mm rear caps, and weighs 720gm. From the maximum aperture I'm guessing it may be a Tessar. Googling has turned up very little beyond other folks' speculation as to its Tessar-ness and a statement that it covers 8x10 (which a 360mm Tessar should, with a small amount of movement). I found one image of another with a serial number close to the mine. Does anyone have any additional real info on this? I am curious.

[IanG]

A 300mm f6.3 is listed in the Komura brochure I downloaded a few years ago as being a lens for 4x5 and 6x9 Press & View cameras, 67mm filter thread. The design is stated to be 4 elements, so a classic Tessar type lens.

That doesn't mean it won't cover 10x8 it's just that was the way Komura marketed it in the Brochure. The f6.3 Tessar designs have the best coverage and are the sharpest. It may well be Komura re-branded it later as a Komura Commercial and sold it as a 10x8 lens.

Ian

[Steve Goldstein]

Ian, I think if you look carefully at that brochure you'll find that the shutter is listed as Copal 1. The lens I have is in a Copal 3S and takes 72mm filters. The info you quoted matches what's on the Cameraeccentric site.

[IanG]

Steve, you're right. However as both the LF Komura 300mm f6.3 lenses are Tessar designs it may have more to do with vignetting on a 10x8 camera with the smaller front/rear cell barrels needed for the Copal 1 shutter, as well as keeping the cost and weight down for smaller format Press/View cameras.

It surprised me how large the Copal 3 (& 3S) shutters are when I acquired my first particularly compared to the Compound #3. It's odd though that there's no readily available literature on the komura Commercial 300mm f6.3 (Copal #3S) they sold quite a few here in the UK.

Ian

[Phil Hudson]

I have a Congo 300/6.3 in a Copal 3s and it is a tessar type design. Image quality is superb - very sharp center and it covers 8x10 fine if memory serves me. I'm guessing it is similar, but not identical to the Komura.

This one has 58mm threads, 58mm rear barrel and a linear aperture scale.

Hope this helps,
Phil

[Lightbender]

if you actually read the previous page on that catalog, it describes the 300mm f6.3 as being a telephoto lens. It is listed as being suitable for a 4x5 or 2x3 camera because the short back focus allows it to be used on 2x3 field or press cameras. this lens will not cover 8x10, but may likely cover 5x7.

You have a very different lens, which is a 'commercial' variety. It is a copy of the kodak commercial ektar, itself a tessar. it should cover 8x10 with a little movement.

[IanG]

if you actually read the previous page on that catalog, it describes the 300mm f6.3 as being a telephoto lens. It is listed as being suitable for a 4x5 or 2x3 camera because the short back focus allows it to be used on 2x3 field or press cameras. this lens will not cover 8x10, but may likely cover 5x7.

You have a very different lens, which is a 'commercial' variety. It is a copy of the kodak commercial ektar, itself a tessar. it should cover 8x10 with a little movement.

It lists and illustrates the 300mm f5 and 400mm f6.3 as being Telephoto, not the 152mm f2.8, 300mm f6.3 0rb400mm f8 so it's rather ambiguous.

Ian

[Carsten Wolff]

I had one of these briefly, about 15 years ago. Image circle may have been just enough for 8x10 (±330mm from memory??). An excellent lens, which I sold, due to not needing it.

[Carsten Wolff]

And no, you're right, one can't rely on the (sparse) specs in the aforementioned Komura catalogue http://www.cameraeccentric.com/html/info/komura_1.html (p.2):
E.g. my (also wonderful) 152mm f3.5 e.g. has a filter size of 72mm, although there may have been a 67mm version about....

[Phil Hudson]

Here's my Congo 300mm f/6.3 in Copal 3s for what it's worth.....