SRT-101 meter needle bounce?

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Theo Sulphate

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After releasing the shutter, is the meter needle supposed to bounce much, if at all? It seems the shock of releasing the shutter, mirror, or whatever, is causing the needle to bounce all the way to the top of the scale and back down.

Can't recall experiencing this on other SRT-101's or any other camera. Doesn't seem like it is good for the meter.


Note: the lollipop needle is fine.
 

albada

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It sounds like something is faulty in the camera, because only the two bearings touch the needle in those cameras. Your camera does NOT use a trapped-needle type of auto-exposure, so nothing should touch the needle while firing. I just fired my SRT-201 a couple of times, and the needle bounced only a little.

Mark Overton
 

Brett Rogers

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After releasing the shutter, is the meter needle supposed to bounce much, if at all? It seems the shock of releasing the shutter, mirror, or whatever, is causing the needle to bounce all the way to the top of the scale and back down.

Can't recall experiencing this on other SRT-101's or any other camera. Doesn't seem like it is good for the meter.


Note: the lollipop needle is fine.

What sort of EV is this relevant to?

It's only the light value that influences the needle of a SRT101 circuit when it is closed. As you've alluded the aperture and shutter settings only couple to the tell tale circle (via those accursed bits of string and pulleys under the top and front covers). At low light the needle is near the top. High EVs have the needle towards the bottom of the finder. So let's think about what happens. If you're metering in medium to high EV, the meter needle is going to be near the middle to lower portion of the finder. When you fire the shutter, the mirror flips up and the EV drops to zero for slightly longer than the duration of the exposure time (allowing for mirror flipping up and descending, afterwards, of course). When the EV goes to 0, the meter is going to head north: this is what it should do and what it should be expected to do. Whether the SRT cuts the power to the meter during shutter release I can't recall without looking up the service manual. It certainly does, if you have engaged the stop down button with an MC lens fitted (but not with, for instance, an M42 lens and adapter fitted as the designers very cleverly ensured one can still use stop down metering with non MC lenses). In any case whether the power is cut to the meter during exposure or, the EV simply drops to 0 (which it WILL, with the mirror up) the needle wants to head straight to the top. When the mirror descends after exposure the EV is going to be restored to whatever it was prior to the exposure. And the needle is going to go straight back down to where it was before.

This is all a more detailed way of saying that your camera may be working quite normally, because I can't envisage how the needle can possibly remain static for the period before, during, and after the exposure. What could be an issue is that the meter scale was originally fitted with a small foam bumper at either end of the needles travel. These act as shock absorbers for the needle (both from impact shock and operational forces I would presume). Sometimes they cause meter issues, too, because they get sticky when they are old and it's not unusual for the top one to glue the meter needle to the top of the scale. If you ever find an SRT with a clean battery compartment and a meter needle that doesn't move after installing a fresh battery into it, unless the battery wires are compromised, there's a better than even chance the needle is simply stuck to the sticky remnants of the bumper foam. And sometimes a DIYer will remove the remains of the bumper and get the meter working, but not replace them with a couple of small foam pieces. Maybe this is a possibility with your camera, because the absence of the bumper foams might exaggerate any ordinary response of the needle to the exposure process?

I'm not sure if I have an unloaded SRT on hand at the moment, but if I do, I'm happy to test fire one a few times to see what the meter is doing with mine. It would be helpful to have some comparison exposure settings to work from though. Obviously there may be more movement starting from EV 15 than from, say, EV 8.
Cheers
Brett
 
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Theo Sulphate

Theo Sulphate

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Thank you Mark and Brent.

In my case, the needle is lower on the scale, closer to the bottom than the middle. I figure that from 1/60 to 1/1000, the overall shutter travel time and blackout period is the same, roughly 167msec (1/60), since only the slit between the curtains changes.

Yet I wonder if the loss of light (voltage) to the meter in this short 167msec period would cause such a rapid rise to the top. Does it really react that quickly? I would expect some movement, just not that much.

When I get home tonight, I'll conduct an experiment: have the exposure set so that the needle is almost at the very bottom (high EV), then quickly put my hand in front of the lens for a moment. I'll see how the needle reacts.

Anyway, I'd like to hear from a few others as well.
 
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Joel_L

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Hi,

I have an SRT102 that I just check and it does to what you described. I think it is exactly because of the reasons given

Joel
 

leicarfcam

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A little needle bounce on all of the srT's is normal. All of mine do it.. In fact all match needle metering cameras will do it too. Afterall when the mirror comes up it blanks out the light being read by the meter so the needle will move a bit..
 
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Theo Sulphate

Theo Sulphate

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OK, I tested the needle movement by momentarily putting my hand in front of the lens for periods of 1/8 to 1/2 second. Yes, as expected, the needle will rise and fall, but it does so with much less rapidity than when tripping the shutter.

However, from what you're all telling me, this is normal. So, I won't worry about it as long as properly responds to light.

Thanks, all, for your replies.
 
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