Experience with "Convertible" lenses?

[mandonbossi]

Hi, I was hoping some of you out there may be able to help me, I am potentially looking at buying a convertible lens, am looking at either the Schneider Symmar 300mm - 500mm or the Symmar 360mm - 620mm. Was just wondering if anyone had any examples to possibly show (both on the long and short ends) and any suggestions overall really.. Also, any idea on what price I might be looking at for these two options?

ok, thanks a lot. Any suggestions or advice would be greatly appreciated!

Cheers

[Bill_1856]

Actually, some of them work really well, but the best way to use them is usually to remove the front element so you better have a LOT of bellows draw available. I mean a LOT!

[mandonbossi]

Oh dear... Had completely forgotten about that one, has been a while since i have used large format gear! I have a Chamonix 45N-1, it says it has a maximum bellows draw of 395mm, any lens suggestions (that don't weigh a ton) that would make use of this maximum bellows? Any telephotos that would enable this longer bellows draw? Or would I be better off with the "360mm f10 Fujinon A"?

Ok, thanks again, much appreciated!

[Doremus Scudder]

My experiences with Schneider convertible Symmar lenses is this. The lens works well with both elements, but is significantly softer converted. This you can ameliorate with aperture and by using a strong filter (orange, red, etc.) to eliminate part of the spectrum and thereby eliminate the effect of the inevitable chromatic aberration.

My Schneider convertibles were single-coated and prone to flare. I got rid of them for that reason.

BTW, I have 240mm and 180mm Fuji A lenses and a love them. The 360mm f/10 should be great for your camera as long as you don't need to focus too close. I have a Nikkor M 450mm that is my longest lens. That needs 20+ inches of bellows draw to use effectively and makes for a pretty big package in use. I can't imagine using a 600mm lens on a 4x5... I can always crop.

Best,

Doremus

[Ken Lee]

I have a Chamonix 45N-1, it says it has a maximum bellows draw of 395mm, any lens suggestions (that don't weigh a ton) that would make use of this maximum bellows? Any telephotos that would enable this longer bellows draw? Or would I be better off with the "360mm f10 Fujinon A"?

If you need a maximum reach with limited bellows draw - but want to focus closer then infinity- then a tele is the way to go. A 400mm Fujinon T (http://www.kenleegallery.com/html/lenses/#400T) will work nicely, as will the 360mm Nikkor T-ED (http://www.fredmiranda.com/forum/topic/770912), 360mm (http://www.schneideroptics.com/info/vintage_lens_data/large_format_lenses/tele-xenar/data/5,5-360mm.htm) or 500mm (http://www.schneideroptics.com/info/vintage_lens_data/large_format_lenses/tele-xenar/data/5,5-500mm.htm) Schneider Tele Xenar lenses.

Given a non-tele 360mm lens and 395mm of bellows draw, how close can we get ?

1/F = 1/D + 1/E where F = focal length, D = distance, B = Bellows Draw

F = 360mm, B = 395mm

1/360 = 1/D + 1/315
1/D = 1/360 - 1/395
1/D = 0.0027 - 0.0025
1/D = 0.0002
d = 5000 mm
Distance = 5 meters or 16.4 feet, and that's pulling the bellows as far as it will go.

It may be easier to find one of those tele lenses than a 360mm Fujinon A - and less money for that matter. The Fujinon A will cost more than your camera, which begs the question of whether the cart is leading the donkey, or vice versa :)

[kgm]

My 4x5 has a maximum bellows draw of 365mm, and the Schneider 400 telephoto works very well on it. It requires only 285mm to focus at infinity, so 395mm gives you a reasonable amount of room to focus closer than that.

[Bob Salomon]

Actually, some of them work really well, but the best way to use them is usually to remove the front element so you better have a LOT of bellows draw available. I mean a LOT!

But the Rodenstock Sironar specifically stated that you remove the rear group. This also protects those delicate aperture and shutter blades not to mention makes it less likely that things get into the shutter itself when the rear group is removed.

And they only start to get sharp, regardless of brand, at very small apertures when converted.

[photonsoup]

But the Rodenstock Sironar specifically stated that you remove the rear group.

My Schnieder Symmar has the converted f-stop and focal length stamped on the rear element, so I've always thought that meant to remove the front element. Ive never used it for that, so I can't say how well it works

89976

[Bob Salomon]

Schneider seemed to recommed removing the front group. Rodenstock the rear group.

[Fotoguy20d]

I have a 240/420 Symmar. It cast a nice image on the ground glass but I don't think I've ever actually used it. At some point I realized it was basically the same as my 9 1/2" Dagor -stopped down, I'm very happy with it converted on my 8x10

Dan

[mandonbossi]

Awesome! Thanks so much for all the responses! So I think with all the advice given, it might be a case of buying a 300mm and cropping. My intention was to focus to infinity, so some options are out.. Unless I am mistaken, the 360mm is uber expensive and telephotos do not give me infinity focus?? To Ken Lee, is that correct? Or i have I missed something here? Also, to KGM, the only references to a 400mm Schneider Telephoto ran somewhere in $2000+ range? IS that correct?

Ok, thanks so much again. Much appreciated!

[Ken Lee]

My intention was to focus to infinity, so some options are out.. Unless I am mistaken, the 360mm is uber expensive and telephotos do not give me infinity focus?? To Ken Lee, is that correct? Or i have I missed something here? Also, to KGM, the only references to a 400mm Schneider Telephoto ran somewhere in $2000+ range? IS that correct?

The 360mm Fujinon A, if you can find one, will almost certainly be expensive.

Telephoto lenses require less bellow draw than normal lenses of the same equivalent focal length.We can focus to infinity, and also much closer than with a normal lens of the same length. When we have a camera with limited bellows extension, telephoto lenses are a good option.

A used 400mm Fujinon T should be an affordable choice.

[mandonbossi]

Hi Ken, Thanks so much for that! She is a large one by the looks of it but used prices seem the goods.. Any idea how much that one weighs? thanks so much for your input, I am very thankful...

[Ken Lee]

Fom my web site (http://www.kenleegallery.com/html/lenses/#400T):

"The Fujinon 400T is a telephoto lens for 4x5: even though it gives a 400 mm effect, it requires only 250 mm of bellows draw. It works great on cameras like the Tachihara wooden field camera - which is otherwise limited to 300 mm lenses of "normal" design. Mounted in a Copal #1 shutter, it takes 67 mm filters and weighs 700 grams. "

[Roger Hesketh]

Looking at cheaper lenses. A 15" Wollensak telephoto only needs about 9" of bellows draw for infinity focus. A Dallmeyer 17" f4.5 telephoto a little over 10".

[Ole Tjugen]

I have the full set of convertible Symmars, and the 360/620mm when converted can JUST be focused to infinity on my large antique 24x30cm camera - with a bellows draw close to 1m. Not a thing to plan for unless you have a huge camera!

[mandonbossi]

Hi, Thanks so much to everyone for the responses, much appreciated! Big thanks to ken Lee for all your help and advice! Will keep a look out for the Fujinon 400T. One last one, is there a longer telephoto that will work with my 395mm of bellows draw? Thanks again.

[Ken Lee]

You might find this thread (http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=002zOm) helpful:

"the Fujinon f/12 600 mm lens requires only 383+ mm extension and Nikkor9s f/9 600 mm lens requires only 409 mm extension at infinity focussing..."

"...there is a lens no one seems to mention and it is perhaps overlooked, it's the Yamasaki Congo T500. This lens is big (15 cm) and has just enough image circle for 4x5". But on the good side, it is short on bellows (287 mm), in Copal #1, weighs only 500 g and has a f9.5 luminous aperture."

Kerry Thalmann has a copy of the Fujinon T brochure on his web site (http://www.thalmann.com/largeformat/ls-ts.htm), and it lists the flange focal length of the 600T as 383.9mm.

If you could find one, it would probably cost more than a new camera. There are several field cameras with much longer bellows, such as the Wisner Technical Field, Ebony, Canham, and even the newer models of Chamonix.

Another option is to get a 5x7 camera and put a 4x5 back on it. Even my humble 1930's Kodak 2D has enough bellows draw to use a 450mm non-tele lens, the Fujinon C. You can get an old wooden 5x7 for a very good price.

If that isn't enough, you can get an old 8x10 wooden camera and put a 4x5 back on it. For an 8x10, 600mm of bellows draw is no big deal.

[mandonbossi]

Hi Ken, Thanks so much again! Will take those options on board. Thanks again, is greatly appreciated!