Graflex.org

worldphoto · Posted: Tue Dec 30, 2003 5:45 pm Post subject:

I deleted the question because this Forum didn't appear to have any interest in the use of positive or negative single lenses to vary the primary lens focal length.

[ This Message was edited by: worldphoto on 2003-12-31 00:32 ]

[ This Message was edited by: worldphoto on 2004-01-08 22:02 ]

[ This Message was edited by: worldphoto on 2004-01-08 22:04 ]

danimal · Posted: Tue Jan 27, 2004 8:15 pm Post subject:

Don't go away mad.

Dan Fromm · Joined: 14 May 2001 Posts: 2144 Location: New Jersey

disemjg · Joined: 10 Jan 2002 Posts: 474 Location: Washington, DC

There was a comprehensive article in View Camera magazine a couple of issues ago that went over the use of these lenses to change focal length.

t.r.sanford · Posted: Tue Jan 27, 2004 11:36 pm Post subject:

There has been discussion on this site of Kodak "Telek" lenses, which I had thought were vanished from photographic memory. They are very useful in certain circumstances, but they have the same drawback as all supplementary lenses (e.g., the old "Sun" Galilean telephoto adapters for TLRs). They degrade the performance of the prime lens, so your enlargements become unsharp at lower magnifications than they otherwise would. You thus confront the alternatives of not using the supplementary lens and making a higher magnification enlargement, or using it and contenting yourself with lower-magnification ones.

RichS · Posted: Tue Jan 27, 2004 11:55 pm Post subject:

Henry · Posted: Wed Jan 28, 2004 12:40 am Post subject:

Gee, now you guys got me thinking, I have a set of Kodak Teleks (-1-2-3-4), also the Portra (+1+2+3) and the Portrait Diffuser lenses, all in series VI and all scrounged at camera shows. I've been wondering why I always carry them around in my bag. Maybe I'll get them out and shoot a roll or two after I dig out from this snowstorm. 'Course it would also help if the temp went up about 60 degrees.

worldphoto · Posted: Wed Jan 28, 2004 5:03 am Post subject:

Thanks for the comments. I have had good luck with my Tiffen positive lenses in Series 7 and 9. They are very good quality lenses. Now some of the cheaper ones were a bust(Vivitar). I have been lucky enough to buy Telek lenses in Series 6 numbers 1- thru 4- on eBay and just a few weeks ago. Total cost $16.02. There are 2" diameter plus and minus lenses on eBay that fit a Series 7 holder. I have as yet not tested them. That is all I need for my 4x5 lenses.
Harry
Okay, for anyone interested,Macnan Biologicals from Birmingham, AL has three positive lenses and three negative lenses for $19.99 plus $7.50 shipping in USA. Look in "Other Lenses. They look good to me but I have not tested as yet.

[ This Message was edited by: worldphoto on 2004-01-27 21:05 ]

[ This Message was edited by: worldphoto on 2004-01-28 21:25 ]

worldphoto · Posted: Fri Jan 30, 2004 8:57 am Post subject:

Rich
Thanks (extra) for your comments. One thing I think we all can agree with is that having adequate primary lenses to meet all our needs would be great! And, any added filter or lens will degrade the image of the primary lens somewhat. What happens when we can't buy all those fancy lenses? We have to look for alternatives. I've been very happy with supplementary lens because they are cheap, light weight, work as either wide angle or telephoto, work on several of my lenses, and just fun to work with.
By the way, what size Telek would you need for your 8x10 lenses?
Harry

[ This Message was edited by: worldphoto on 2004-01-30 01:17 ]

RichS · Posted: Fri Jan 30, 2004 3:56 pm Post subject:

t.r.sanford · Posted: Fri Jan 30, 2004 4:25 pm Post subject:

A couple of points -- could you attach the supplementary lenses to the rear group of your convertible lens? I suppose you'd need a push-on adapter ring, or something with a setscrew, to do this. Tiffen makes (or used to make) all kinds of unusual adapter rings, and a note to them might be enlightening.

Or, if this is something you mean to do a lot, it might be worth finding a machinist to make an adapter ring (or rings) with the same mount diameter and thread as the front group of each lens, that you could screw directly into the shutter. This might simplify using filters and other front-lens attachments, too. I suspect the Steven Grimes outfit could do this easily.

It really is too bad that negative lenses of long focal length and fairly large diameter, say up to three inches, are so difficult to come by.

It also is too bad that the modern optical design industry has not dusted off the late-19th Century telephoto attachment designs and come up with a well-corrected teleconverter that could be mounted behind a large-format lens. I suppose there is not a lot of demand for such things, i.e. millions of people are not clamoring to buy them at Wal-Mart, and "niche" markets fare poorly in these mass-merchandising days...

RichS · Posted: Fri Jan 30, 2004 5:46 pm Post subject:

Hmmm, never actually thought of it. Unfortunately, I don't do anything photographic a lot of the time...

I don't see any reason why it couldn't be mounted in the rear? That brings up the old problem of finding push-on adapters which never came in the larger sizes I would need... But something like that is easily fabricated one way or the other.

I think the real killer of such things is the availability of cheap 35mm lenses. That's the big market. When I started out, everyone bought tele-extenders because we couldn't afford tele lenses. Now you can get a 9:1 or so wide-to-tele lens for a hundred bucks. Who would buy 'telek' lenses for even $50? Just a small niche market. Close-up lenses maintain a broader market because it's really the eaisest and cheapest way to do macro and most people can easily understand how to use them. Although in the same 'cheap' line, I still have my original set of 35mm extension tubes, not even auto-arperture...

But considering some of the other niche stuff available, I'm surprised that no company has produced a telek set. It could easily be done in one size with adapters to fit smaller lenses, again to save money. I'm sure it would sell enough to at least pay for the design

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Dan Fromm · Joined: 14 May 2001 Posts: 2144 Location: New Jersey

t.r.sanford · Posted: Fri Jan 30, 2004 6:35 pm Post subject:

If memory serves, the early "Adon" was a weak Galilean telescope, like the front-mount "telephoto" attachments for today's digital cameras (and yesterday's 8mm. movie cameras, and TLRs). There were a couple of other 1890s attachments that mounted behind the prime lens and worked like an astronomer's Barlow lens, or a modern teleconverter. I gather that they were not successful because modern optical glass manufacturing methods had not been invented yet, and designers were unduly restricted. Also, of course, computer ray tracing programs lay far in the future.

This is the sort of thing Wisner might take up, and charge $3000 for, when completed.

I've sometimes used an old Spiratone
"Curvatar" -- an 0.5X wide-angle attachment that can produce a fisheye effect when used with a WA lens -- on a 4X5 camera. I hadn't thought about the possibilities in a 1.5X Galilean attachment, which would make a 203mm. lens act like a 12-inch one, with no increase in extension and no loss of effective aperture. At f:11 or smaller, this might be very well worth doing, under certain circumstances.

RichS · Posted: Fri Jan 30, 2004 8:01 pm Post subject:

I have a cheap .5x(I think) front attachment I bought years ago when video-cams first came out. It was the only way to effectively shoot indoors with the thing. Never really used the vidcam, but I have used the attachment on my C330. I had put it in with the 4x5 stuff thinking I would use it, and it does provide a nice wide effect, but far from quality. The distortion is easily seen on the GG. Great for some kind of special effect I suppose...
They do make better quality ones, but at quite a cost. No doubt front mounted tele options, and I recently saw a "Plus Diopter" aspheric attachment that ran somewhere around $3000 I think. Hmmm, maybe $300. It was high priced enough that I didn't pay enough attention to it

I'm sure there's cheaper ones available now for digital cameras. The only problem is they usually have very small diameter lenses...

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"Ya just can't have too many GVIIs"

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