Seiko shutters - and that "flying" arm...

[Christopher Perez]

I spent a little time on Saturday tracing down a suspected challenge with one of my new lenses. I had picked up a barrel optic and screwed it into a #0 Seiko shutter. My first images left me to thinking there might be something wrong.

The Seiko (for those not familiar with it) throws its cocking lever rather hard when the shutter is tripped. I was concerned that this might be a source of my perceived resolution challenges.

I tried the optics in both the Seiko and Copal shutters and took a close look at the resolution on-negative. There is no difference between. So I'm comfortable now with the Seiko and it's "flying arm". :-)

And the lens? Its sharp. I don't know what I was worked into a lather about...

[Darin Cozine]

so what was this lens?

[Scott Davis]

It could well be that the lens elements (if the lens you mounted has separate front and rear elements) are no longer in alignment. If the entire lens is either front or rear mounted on the shutter, then it is possible that this is a vibration related issue with the shutter, but since you had the problem across two different shutters, I find this less likely.

[Christopher Perez]

The lens was a new 150mm Germinar-W f/9. Its a very nice optic. Images are as nice as ones from my 150mm Fujinon NSW f/5.6, which is a beautifully sharp/contrasty lens.

What I was comparing against was an even better 300mm APO Germinar f/9. I'll have to haul out the USAF test chart to see what this resolves. From the looks of things, its a brilliant optic, if not a little short on coverage.

I can see a very slight difference between the Germinars, but only in highly magnified comparisons (where I can clearly see the grain in TMax100/D76 negs). On-print there are no visible differences.

Like I said, I don't know what I was all worked up about.

[Jim Galli]

Tsk. A German lens in a Japanese shutter? You need to go find a Compur for that. Some of your old C59 Tektronix CRT cams have a spiffy little Prontor that would be perfect. :~')

[Christopher Perez]

Ah... Jim. You are a gem. Of course! Why didn't I realize this earlier? Nothing like a few 'ol Prontors laying around, ready to be sent to the scrap heap to make a grown man cry.

[Darin Cozine]

Back to the topic of seiko shutters, I allways thought that they were a copy of compur shutters, and I dont remember the vibration from my SA in a Seiko to be any more than that of a compur. I will check it out when I het home.

[Christopher Perez]

The Compurs that I've seen run smoothly and quietly. I don't recall the cocking lever swinging the way the Seiko shutter arm does.

[Kerry L. Thalmann]

While the Seiko shutters may have the same thread sizes and nominal cell spacing as the Compurs, they aren't exactly copies. The Seikos have to be cocked to open the shutter blades for composing/focusing. Compurs don't (of course, not all Compurs have a press focus setting - some have to be placed on B or T for focusing/composing).

The Compurs went through many iterations over their long life. Some (No. 2 rim set Compurs, for example), did have a "flying arm" like the Seikos that result in a loud "thunk" upon the closing of the shutter blades. Like the Seiko, any induced vibration occurs AFTER the blades are closed. So, while it may be a bit unnerving, there should be no impact on sharpness.

Kerry

[Jim Rice]

Copals are Japanese, right? So if multicultraliasm results in blonds with those eyes is that a bad thing?

[David Honey]

Almond-eyed blondes aside..(!)

Why exactly are Seiko shutters less desirable than Copal?

Is it because of the 'flying cocking lever', or is it that they lack a separate diaphragm-opening lever?

Are there other drawbacks?

Can anyone straighten me out on this -- there's a nice lens I want to buy and it's a lot cheaper with the Seiko shutter.

Thanks

[Mike Kovacs]

My MC Schneider Super Angulon 90/8 is in a Japanese Copal shutter too. Remember Copal?

The Copal is notably inferior to the Synchro Compur's I own in terms of build quality, noise and vibration IMO. I've worked on a Seiko but don't have one at the moment. Can't recall when the lever hits - at the beginning or the end of the shutter cycle? Of course, vibrating at the end of the shutter cycle would have no effect. The Seiko seemed like a decent enough shutter quality wise. No worse than a Copal IMO.

[Kerry L. Thalmann]

The cocking arm hits at the end of the cycle. Also, at least on the Seiko No. 0 shutters I have, there is a separate diaphram-opening lever that can open the lens for focusing. However, it can only be used to open the diaphram after the shutter has been cocked.

Kerry

[John_4185]

Sir Perez . I'll have to haul out the USAF test chart to see what this resolves.

oooooh! Tone it brown, sign it and put it on that auction site!

[David Honey]

So what's the verdict? Condition and vintage being equal, you'd be as well off with a Seiko shutter as a Copal?

Is there usually a price differential? If so, what is it based upon?

Thanks

[Mike Kovacs]

I would say the differential exists because Copals are still being made while Seikos are not. Haven't had a 1970's Copal and brand new Copal open side-by-side, so I cannot comment if its justified by parts still being available.

[David Honey]

Well, I just got a Fujinon 90/8 SW in a Seiko #0 shutter, and I can tell you that the 'flying' cocking arm makes a disconcertingly huge 'clank' at the BEGINNING of the shutter cycle. You can plainly observe this at the lower shutter speeds. It's a bit off-putting.

Having dealt with the issue of 'mirror slap' in 35mm and dSLR cameras before, I think the flying arm is a pretty good contender for creating some image-disturbing vibration.

That is, if one were to worry about such things... which I'm not inclined to do right now

...seeing as I just bought the lens, and I'm too broke at the moment to trade up to another lens or a Copal shutter.

Maybe after Christmas...