Enlarging Lens for 6X7

[Thilo Schmid]

I used to have a Rodenstock 105mm for 6 x 7, but now have a lens I have never seen anyone else using. It is a Taylor-Hobson, f4.5, 108mm Ental and will cover up to 6 x 9 ... I have no idea how old it is (does anyone know anything about the things?). It was made in Britain and we don't really have much of an optical industry any more so it is probably as old as me, but it is good.

David,
you shouldn't be that pessimistic about UK technology. Taylor-Hobson is not only still in the optics business, it is even a direct competitor of companies like Zeiss. They once made the famous Cook lenses and were the first ones that built zoom lens in series. AFAIK, they still make cine lenses.

Ental was originally a Tessar (4-element) design. Tessars are usually top sharp and contrasty around the center of the image circle. With 6x7, you utilize mainly this part of the lens.

I don't know when Taylor-Hobson stopped making enlarger lenses or when the brand name was discontinued (which could have been two different events). I guess it has been somewhere in the late 70s.

 

[Maine-iac]

Chuck,

the 80mm Componon does not cover 6x7, so your observation should be normal. I don't know your enlarger, however, it makes me wonder that it does not have enough bellows for 80mm@1:3.5.

Since when? I've been using an 80 Componon (first the old model, then the latest model for the past 8 years) and have never had coverage problems with 6X7. I have both a 6X7 Fuji rangefinder and a 6X7 back for my 4X5, and shoot this format almost as much as I shoot 645 or 6X6. I'm using a Beseler 45 with a Dichro colorhead.

Larry

 

[Konical]

Good Morning,

I had the same experience as Larry with the 80mm Componon. I bought one used back in the '70's and used it successfully with 6 x 7 for over twenty-five years. Eventually, it developed an internal haziness on the lens elements, so I had to replace it. As in Larry's case, I used it on a 45-MCRX enlarger. Coverage with 6 x 7 was tight, but very acceptable.

Konical

 

[Thilo Schmid]

Since when? I've been using an 80 Componon (first the old model, then the latest model for the past 8 years)

Are we talking about Componons or Componon-S? AFAIK, there was only one Componon 5.6/80 and that dates back to the 60's. The later model Componon from the 80's have only been 28/35/60. Coverage depends, of course, on the mag-ratio. Even the current Componon-S 4/80 is not supposed to cover 6x7, which means that it does not fulfill the manufacturer's quality criteria for that format - at least at the declared maximum mag-ratio. Otherwise he would have written in the specs that it does cover 6x7.

 

[Konical]

Good Afternoon, Thilo,

Mine had to be the older model. It was used when I bought it in the mid-'70's.

Konical

 

[dancqu]

...which means that it does not fulfill the
manufacturer's quality criteria for that format -
at least at the declared maximum mag-ratio.

Of enlarging lenses in general, do you know of their quality
of performance at less than the maximum mag-ratio? Also,
is that maximum mag-ratio the lens' designed optimal
magnification? Dan

 

[Thilo Schmid]

...is that maximum mag-ratio the lens' designed optimal
magnification?

Usually not. The maximum mag-ratio is a figure where the lens still reaches a certain quality criteria, but its optimum performance is usually somewhere between the min and max ratios stated in the tech specs. This is especially the case when a lens is supposed to work in a larger range (e.g. 1:2 to 1:15). There are some special lenses around that were designed to work with a single or a limited range of mag-ratios (e.g. special lenses for slide duplication). These lenses are excellent within the whole range.

 

[craigclu]

Up to 8X10 (from 6X7), I can't tell the difference between my Rodagon 80, Schneider APO 90 and Comp S 105. I've tried a number of times, I've also had others inspect and it keeps returning the same verdict. Something happens at 11X14 and up, though. Then the APO starts to show some advantage but it is really quite small in difference. I'm glad I have it and I find I use it for about 75% of everything I do, even 35mm as I tend to not print beyond 5X7 regularly with 35mm. Used examples of all of these are floating around at such affordable prices, I'd lean toward buying the best glass you can find and get that bottleneck out of your quality trail....

 

[dancqu]

I did'nt quite ask the question I ment to ask. As the lens magnification
lessens, coverage increases at the negative. I was just wondering if that
additional coverage is of any value. For example will a 50mm lens
do well with 2 1/4 square at 1:1 or perhaps 1:2? Dan

 

[Thilo Schmid]

I was just wondering if that additional coverage is of any value. For example will a 50mm lens do well with 2 1/4 square at 1:1 or perhaps 1:2? Dan

Although I have not yet tried this, I wouldn't expect much from it. 50mm lenses usually start working at 1:5. However, you won't see anything critical below a 5x7 print size anyhow.

 

[Maine-iac]

Are we talking about Componons or Componon-S? AFAIK, there was only one Componon 5.6/80 and that dates back to the 60's. The later model Componon from the 80's have only been 28/35/60. Coverage depends, of course, on the mag-ratio. Even the current Componon-S 4/80 is not supposed to cover 6x7, which means that it does not fulfill the manufacturer's quality criteria for that format - at least at the declared maximum mag-ratio. Otherwise he would have written in the specs that it does cover 6x7.

My old 5.6 Componon was a 1960's vintage--small diameter screw mount.

The new one, purchased about 8 years ago is an f4 Componon-S and is, indeed, an 80mm. I bought it to replace the older one when I was printing a lot of Ilfochromes and needed the extra stop to shorten the exposure times. Whether or not the manufacturer's specs call for it to cover 6X7, it does quite nicely. Maybe it's due to the bellows length and 4X5 mixing chamber on my dichro head, but whatever, it works.

Larry

 

[fschifano]

My 80mm Componon-S must be one of the later ones. It covers a 6x7 negative in my Omega D-4 if you stop it down about 3 stops and delivers pretty good results on an 8x10 enlargement. Your problem with focusing is surely due to a lack of bellows extension. If you can get a lens cone to match your lens that problem will go away. You need to increase the distance between the lens and the negative.