View Full Version : Bought a used Schneider 150 Symmar-S; aperture seems wrong

11-Dec-2006, 13:43
Hi all,

I just purchased a 150mm f/5.6 Schneider Symmar-S MC on a Copal #0 from the "auction site." I haven't shot with it yet, but the aperture scale seems wrong to me. The rear diaphragm opening appears to be 24mm (http://clients.brettsimison.com/media/schneider_150/BJS-20061211_1519-01.jpg), meaning that wide open, the aperture is effectively f/6.3 (150mm / 24mm = 6.25). This is at its widest setting, with the aperture ring indicator pointing far "outside" the scale above the 5.6 marking (http://clients.brettsimison.com/media/schneider_150/BJS-20061211_1519-00.jpg). Stopping down to the 5.6 marking (http://clients.brettsimison.com/media/schneider_150/BJS-20061211_1518-01.jpg), the aperture blades close to 14mm (http://clients.brettsimison.com/media/schneider_150/BJS-20061211_1518-00.jpg), meaning the f/5.6 setting is effectively f/11 (150mm / 14mm = 10.7).

Does this mean that this Copal #0 shutter isn't matched to this lens? Is my math wrong? Will I need to replace the shutter, or simply have it recalibrated?

Thanks in advance for your answers!

Brett Simison

JW Dewdney
11-Dec-2006, 16:42
Shoot with it and see what the film thinks. If it HAS a 'mixed-and-matched' shutter - why not just offset for the error that it seems to have? i.e. If f/11 indicated should really be f/8, then just knock it back a stop from what the meter tells you. Seems like that would be cheaper and just as effective as far as your photography goes than having the shutter 'doctored' - less expensive, too. I suppose it really depends how much work you're doing with it too.

Frank Petronio
11-Dec-2006, 17:09
I bought a nice looking lens from the auction site -- a 300/5.6 -- but it came in a shutter marked for a f/6.8 lens. Idiots and Liars mix and match and I got screwed. LensN2shutter or Grimes can make new scales. I got a refund but the SOB refused to refund my shipping because he said it came from a "working studio that never had a problem" and I am too lazy to complain further other than to cast a Voodoo curse his way.

So some a-hole took and extra shutter and stuck the lens cells on it, without thinking that it mattered or ignoring the disservice. CALL THE SOB ON IT AND SCREW HIS A$$ TO THE WALL.

I have no pent-up anger ;)

Chauncey Walden
11-Dec-2006, 19:46
Brett, I think you need to measure the apparent opening from the front to do your calculations.

11-Dec-2006, 20:14
Brett, I think you need to measure the apparent opening from the front to do your calculations.

Hah! Really? Wouldn't have thought of that. I'll give that a try and see how that changes my numbers.

I'll also put the lens on a camera and take a few test shots, comparing them against my meter and a known good lens.

According to the SKGrimes website, it would cost me ~$80 to get a new, calibrated aperture scale for this lens.

11-Dec-2006, 21:31
The scale does look off and even later addition. Did you look what's under the scale strip?

The aperture scale of Copals is linear, so you should be able to DIY calibration if the both ends (open=5.6/closed=45) are true (acceptable) by measurement and test results. It seems worth trying before coughing up $80. And Frank has a point...the seller owes you $80 (plus a couple of million for the emotional trauma you are going through:-). I'd try to get some of it back and record the issue in feedback--particularly if you end up returning the lens.

Dan Fromm
12-Dec-2006, 05:30
Brett, Copal shutters' aperture scales come in a long roll of metal tape. When a shutter needs a scale, one is cut off the roll and trimmed to put the pointer over the lens' maximum aperture when the diaphragm gives that aperture. Holes for the mounting screws are then drilled in the scale and it is attached to the shutter body.

Your shutter's aperture scale is in the wrong position for the lens now mounted in it. End of discussion.

Hiro's comment is bang on. You have a scale so you know the distance between stops. So making your own scale -- adhesive backed paper, for example -- finding where f/5.6 is on it, and then marking the smaller stops' positions is no big deal.

I really don't like to agree with Frank, but this time he's right too.



12-Dec-2006, 07:24
Thanks, everyone, for your replies. I've emailed the seller and requested a discount in the amount estimated to install a new scale, or a return and refund. This will be noted in their feedback regardless.

I removed one of the scales and the lens barrel is blank underneath, so I'm guessing this shutter must have been taken from a different lens, although I'm still at a loss for why a shutter would be marked with the largest aperture of 5.6 marked so far down the scale.

If I were to go the DIY route with this, would I mark 5.6 at the point in the aperture scale where the blades are just out of the image area, or completely wide open, with the aperture tab "floored" all the way to the right?

Thanks, again!

Dan Fromm
12-Dec-2006, 08:45
Brett, there were shorter f/5.6 lenses, and for them the f/5.6 hole is smaller than a hole that's f/5.6 with a 150 mm lens.

After the blades are out of the entrance pupil, they're out of it. Wide open = f/5.6 is when the blades are just out of the pupil.

I just went through a similar exercise with a Copal 1 scaled for a 127/4.7 Tominon. Put some 105/5.6 Saphir BX cells in it and lo! marked f/8 is exactly wide open = true f/5.6.