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dh003i
28-Dec-2008, 18:40
Hi all,

I have seen many say that the number and shape of aperture blades doesn't significantly affect the quality of out-of-focus rendition (bokeh pattern). However, articles by Harold M. Merklinger (http://www.google.com/url?sa=t&source=web&ct=res&cd=1&url=http%3A%2F%2Fwww.trenholm.org%2Fhmmerk%2FATVB.pdf&ei=QjdYSYfJGoGCtweW35CrDg&usg=AFQjCNEzviMvnMoEwGzDy77lRoiga4CGsg&sig2=Rq7ZD7rx2ZRsjlPsU6LmUQ) and Christopher Perez (http://www.hevanet.com/cperez/test/BigMash210.html) suggest otherwise.

Perez' tests show improvements in out-of-focus rendition by remounting a Schneider Convertible 210mm f/5.6 from a 5-bladed #1 Copal shutter to a 10-bladed round-aperture Prontor. He suggests remounting lenses in shutters with more aperture blades. However, looking on eBay, I can't seem to find many shutters for sale; any suggestions?

DuncanD
28-Dec-2008, 19:04
http://www.skgrimes.com/repair/repshut/index.htm

Frank Petronio
28-Dec-2008, 20:25
It's a lot easier just to buy older lenses and have them cleaned and adjusted than to deal with remounting. For the sort of lenses and subjects where you care about bokeh and short depth of field, you will probably be fine with a nice 1950-60s German single-coated lens in a nice Compur shutter -- perhaps they won't be as sharp as a recent Sironar-S in their Copals, but you'd be splitting hairs.

Ole Tjugen
28-Dec-2008, 21:39
Compounds are nice - the Compound #5 has 23 aperture blades. They don't come much rounder than that!

The only problem is that newer lenses aren't compatible with the nice old Compounds - even the #3 is different from a Copal #3. That's why I'm glad I found an old 355mm f:9 G-Claron - a drop-in fit in a Compound #3 which it now shares with a 210mm f:4.5 Xenar. ;)

Turner Reich
28-Dec-2008, 22:21
What about barrel lenses with slots for Waterhouse stops?

Ernest Purdum
30-Dec-2008, 10:52
I would think (never tried it), that the small apertures of process lenses might make it difficult to get desired out of focus areas as close as you want to the subject.

Ken Lee
30-Dec-2008, 11:17
For the cost of having just a few lenses mounted in shutter, you can get an entire Sinar camera, and a Sinar shutter.

Then you can use all the vintage and barrel lenses you like, using their many-bladed diaphragms.

That's what I did.

You end up with a superb camera, and a modern self-cocking shutter that provides accurate timing from 1/60 second to 8 seconds.

Even though they used a slide rule instead of a computer, the makers of vintage lenses were no fools. They took the extra trouble to make multi-bladed diaphragms, for a reason.

Glenn Thoreson
30-Dec-2008, 11:37
A #1 Prontor Press shutter would give you ten blades without mounting cost. Your Symmar, if in a Copal #1 now, will screw right in with no problem. The problem lies in finding a #1 Prontor Press shutter. They're hard to find. I just got one off the auction site in perfect condition, with correct aperture scale for my lens, for 60 bucks. Mostly due to the hazy description and being listed as a Copal. Ya gotta keep yer eyes open. I'm a happy critter, I am.... :D

Steve Hamley
30-Dec-2008, 11:52
I think the operative word is "significant". Chris' experiment does show some improvement with large magnifications on small high-contrast areas, but I doubt there's much of an observable difference in real life prints viewed at normal distances. One of Chris' other articles also mentions that the vintage lenses he tried were in many cases virtually indistinguishable from the modern ones when used appropriately, which would seem to contradict the implication that there was much difference resulting from aperture blades. Maybe Chris will comment.

I find myself becoming more Frommish in my opinions as I experiment with more lenses. I see little if any difference between a B&L 4.5 Tessar and a Heliar, and the designs are somewhat similar. I can see a large difference in lenses that WERE designed to be different, for example a soft focus lens and a modern plasmat. I can also tell the difference between the diffusion of the "dial up" lenses like the Cooke and Universal Heliar, and the aperture-controlled softness of a Veritar, Kodak, etc.

Cheers,

Steve

Ken Lee
30-Dec-2008, 12:09
I made some photos which compare Heliar, Tessar, and Sironar-S. I'll try to scan and post them soon.

Dan Fromm
30-Dec-2008, 12:20
Hokeh? Bokeh? Well, bright out-of-focus points can be rendered as images of the diaphragm. Think of the classic movie shot done with a high ratio zoom that has millions of bright hexagons all in a row. That's not what most people mean by bokeh. Otherwise the shape of the aperture has no effect.

dh, are you planning to shoot against the light? Sunlit ripply water? Night scenes with lights in them? I ask because these and other similar situations aside, one has to work to get bright out-of-focus highlights. If you haven't yet got unsatisfactory bokeh with your old Symmar, try before putting more money in it. It may surprise you pleasantly, Copal shutter notwithstanding.

Thinking of old Symmars, what is it doing in a Copal? Most convertible Symmars were delivered in Compurs that had more than five blades.

Glenn Thoreson
30-Dec-2008, 18:39
Dan, that's what I thought, too. Compurs. I needed a Prontor Press to replace a thoroughly busted one which held an outstanding example of a 150/4.5 Xenar. I guess the photo taking of an operating MRI machine did the old shutter in. It wouldn't stay fixed, then it died a horrible death.

Drew Wiley
30-Dec-2008, 19:05
More aperture blades equals rounder out-of-focus highlights. "Bokeh" is a relatively
subjective term, but this is one of its main ingredients in any format. Note that Nikon actually uses curved aperture blades on their current 85/1.4 to obtain a rounder-appearing aperture. Ninety percent of the time I'm shooting around f/45 with an 8x10 and could care less. But there are those moments when I dig out the
Dagor for just this purpose. Love those older apertures when you need to shoot
relatively wide open.

Frank Petronio
30-Dec-2008, 22:09
All the Leica, VC, and Zeiss lenses have pretty round apertures... it's the consumer grade Nikon and Canons that have only five-bladed hexes. But I was surprised to see than Rolleiflexes, which have excellent bokeh, also have hexagonal apertures, even the 2.8.

The cheap practical solution is to always try to shoot wide open, don't stop down. Used wide open every lens has a circular aperture. That's how I use my Nikkor primes (24/2.8, 35/2, 50/1.8) on my DSLR.

dh003i
3-Jan-2009, 11:38
dh, are you planning to shoot against the light? Sunlit ripply water? Night scenes with lights in them? I ask because these and other similar situations aside, one has to work to get bright out-of-focus highlights. If you haven't yet got unsatisfactory bokeh with your old Symmar, try before putting more money in it. It may surprise you pleasantly, Copal shutter notwithstanding.

I sometimes shoot against the light, or in places with light from many sources. I like shooting locally near where I work, at the bleachers at RIT and the parking lot at the Univ. Rochester CVRI. I have taken some portraits there of my cousin (http://www.tabblo.com/studio/stories/view/1686060/), and like the interesting mixture of blue and yellow lights. As you can see, some of those shots have bright lights in the background. As you can see from those shots, sometimes, my rokkor 58/1.2 produces blotchy OOF highlights for bright points (I think I read the textured OOF appearance there is due to coating imperfections some lenses have). But the shape of the aperture does come into play.

Those shots also illustrate the reason for me using that 58/1.2 lens on my DSLR: speed. Looking at the data for one shot, I had to use ISO-400, for about 1/3rd of a second. Assuming the typical f/4.5 with ISO-100 film for LF, that would necessitate an exposure that is 56 times longer [(4.5/1.2)^2 * 4] or 18.75 seconds. That would seem a little bit long to ask anyone to sit still. (but assuming ISO-400 film, it's only be 14x as long, so 4.7 seconds)

Gordon Moat
3-Jan-2009, 12:02
Actually, a better approach in low light with large format is to use a small pop of flash or strobe. The main exposure is handled by the strobe, then you can leave the shutter open to record the ambient light level. If your model/talent is reasonably still, the up to two to four seconds is no problem, because the strobe freezes the important detail. I don't suggest trying this with kids nor animals, unless you can duct tape them to a chair.

If you shoot wide open with large format, then the aperture shape is round. While some lenses do not work well that way, there are several f5.6 lenses that perform nicley wide open.

Ciao!

Gordon Moat Photography (http://www.gordonmoat.com)

Dan Fromm
3-Jan-2009, 12:06
Thanks for posting the shots of y'r cousin. Try the Symmar wide open before spending money, it may surprise you. It has fewer air-glass interfaces than y'r 58/1.2 Rokkor, will produce fewer images of the diaphragm.

Good luck, have fun,

Dan

tim o'brien
4-Jan-2009, 00:35
Dan, that's what I thought, too. Compurs. I needed a Prontor Press to replace a thoroughly busted one which held an outstanding example of a 150/4.5 Xenar. I guess the photo taking of an operating MRI machine did the old shutter in. It wouldn't stay fixed, then it died a horrible death.

Learn sumthin gnu every day. I have a Prontor press shutter and a 150/4.5 Xenar barrel. Never even thought to put the two together. Tomorrow.

tim in san jose