QL17 GIII: Question regarding aperture

[FTography]

Heya folks,

today I received my Canonet QL17 GIII in the mail. Currently, there is no battery in the camera, but nevertheless I wanted to test the camera's functions as much as possible.
The shutter is firing as it should and it appears to me that the shutter speeds sound about right.

But now to where I could use some feedback from other owners of the camera. Without the battery, it seems that my Canonet will not adjust the aperture, no matter to which aperture the aperture ring is set to.
Is this normal behaviour? Is the aperture set electronically and, as i am not using a battery right now, will not be adjusted correctly without electric power?

I'd appreciate any feedback other users could give me.

Greets F

 

[ka1axy]

I just had the front lens elements off my 'bay Canonet this weekend. My aperture varies as I adjust the ring. As long as it is not set to A, you should be able to move the aperture. While I was degreasing the shutter, however, I noticed that the aperture was not changing.

The aperture mechanism uses very light forces and just the excess naphtha that had found its way between the blades was enough to prevent the aperture from moving. As soon as it evaporated ( an hour in the sun), the aperture blades moved freely.

Mine's a Hong Kong Canonet and the front lens elements removed as a single assembly (though it initially took quite a bit of force to turn the threads, which were gummed up with something, probably lubricant). When I got it off, exposing the aperture and shutter blades, I could see the retaining rings for the front and rear elements had drops of sealant on them. It's not really that hard to get the front lens assembly out, and a good cleaning of the blades couldn't hurt. My shutter and aperture work fine now.

Unfortunately, the front lens element has a good deal of scratching on it and the rear element shows tendrils of mold. So it's now a candidate for resale to someone who has a bad body with good lens elements.

 

[ghostganz]

The aperture usually works fine without a battery.

I don't have the camera in front of me, but if I remember correctly you should see the aperture moving within the lens as you adjust the aperture setting. Maybe depending on whether the shutter has fired or not.

If you don't have film in it you can fire the shutter with the back open on different aperture settings, and you can verify directly by looking through the lens if the aperture size has changed.

 

[oftheherd]

I don't have mine in front of me either, but if I recall, some models allow the aperture to change only when the shutter is tensioned.

 

[Gabriel M.A.]

Without the battery, it seems that my Canonet will not adjust the aperture, no matter to which aperture the aperture ring is set to.

1) if the ring is set to A, the aperture will not be Automatically set if there's no battery.

2) if anything other than A is selected, the aperture will be set properly when you fire the shutter (meaning, you may not see the aperture blades move while you move the dial, but they will when you fire the shutter).

 

[FTography]

The aperture usually works fine without a battery.

Thanks for your feedback. The aperture blades positively don't move as I adjust the aperture ring. :bang:

I just had the front lens elements off my 'bay Canonet this weekend. My aperture varies as I adjust the ring. As long as it is not set to A, you should be able to move the aperture. While I was degreasing the shutter, however, I noticed that the aperture was not changing.

The aperture mechanism uses very light forces and just the excess naphtha that had found its way between the blades was enough to prevent the aperture from moving. As soon as it evaporated ( an hour in the sun), the aperture blades moved freely.

Mine's a Hong Kong Canonet and the front lens elements removed as a single assembly (though it initially took quite a bit of force to turn the threads, which were gummed up with something, probably lubricant). When I got it off, exposing the aperture and shutter blades, I could see the retaining rings for the front and rear elements had drops of sealant on them. It's not really that hard to get the front lens assembly out, and a good cleaning of the blades couldn't hurt. My shutter and aperture work fine now.

Thanks for your elaborate comment, that sounds promising. How'd you get the front lens element out of the lens barrel? Are there any special tools required for me to do it? I am not that eager to spend more money on a repair than the camera cost me.

 

[FTography]

1) if the ring is set to A, the aperture will not be Automatically set if there's no battery.

2) if anything other than A is selected, the aperture will be set properly when you fire the shutter (meaning, you may not see the aperture blades move while you move the dial, but they will when you fire the shutter).

I already suspected the automatics not to work w/o a battery.
I was of course referring to setting the aperture manually. It appears my camera is stuck at an aperture of 16, as the blades are quite closed. If I set the camera to an open aperture such as the max. 1.7, and fire the camera in bulb, holding the shutter release button, the aperture does not open.

 

[ka1axy]

Thanks for your elaborate comment, that sounds promising. How'd you get the front lens element out of the lens barrel? Are there any special tools required for me to do it?

I'm nothing if not elaborate (I'm an engineer)! It was easier than I expected, actually.

Instructions:
http://www.rangefinderforum.com/forums/showthread.php?t=90468
http://www.rangefinderforum.com/forums/showthread.php?t=8497

Using the small end (pointy inside measurement blades) of the calipers (below), remove the silver retaining ring that holds the black name plate on. Once this (and the photosensor aperture plate) are removed, you'll see the black ring that removes the front lens element. I used a pair of pliers with the tips ground to fit the spanner slots. If the ring refuses to turn, try dripping some Ronsonol down the side.

I had to put a lot of force on the ring to get it moving, but as I turned it got easier. It was quite gummed up, but as far as I could tell, this was not sealant or lacquer. The two lens elements came out as a unit, exposing the shutter and aperture blades. I got quite good at holding the shutter open in B mode, which allowed me to clean the Ronsonol residue off the front element of the rear lens unit.

There is also a repair manual: http://pentax-manuals.com/manuals/service/canonet_giii.pdf
and a bit of googling will get you all manner of suggestions and information. Some will suggest going in from the back, I found the front worked fine for me.

The battery compartment will accept an unmodified SR44 cell (small bump contact goes to minus, flat springy contact goes to plus), which will make the meter work. Inside the top cover, is a variable resistor, which you can adjust to account for the difference in voltage between the SR44 and the unavailable mercury cell. No adapters needed, just a recalibration by adjusting this resistor.

Tools:
Remove outer ring: http://www.generaltools.com/Products/Metric-and-English-Vernier-Caliper__722.aspx
Remove front lens unit (grind down the tips w/Dremel tool): http://www.generaltools.com/Products/Long-Needle-Nose-Pliers__905.aspx
Dividers for use on spanner rings (grind down tips to fit):
http://www.amazon.com/Inside-Outsid...3?ie=UTF8&s=home-garden&qid=1302703485&sr=8-3

Clean using Ronsonol lighter fluid and a q-tip or paper towel held in tweezers, and keep activating shutter and moving aperture to work the liquid through. Remember aperture won't move until Ronsonol evaporates.

 

[ka1axy]

Now that I think about it, I believe Gabriel M.A. is correct, the aperture blades move only when you fire the shutter. I think I could move them by turning the aperture ring if I put the shutter in B and held it open.

 

[FTography]

Now that I think about it, I believe Gabriel M.A. is correct, the aperture blades move only when you fire the shutter. I think I could move them by turning the aperture ring if I put the shutter in B and held it open.

As can be seen, the shutter blades will open when the shutter release is pressed.
(Here, I've used a lockable remote trigger cord to fire and hold B.)

Here it is obvious, that despite setting the camera at f1.7 (and B), the aperture blades do not open when the shutter is open.

Thanks for your elaborate comment, that sounds promising. How'd you get the front lens element out of the lens barrel? Are there any special tools required for me to do it?

I'm nothing if not elaborate (I'm an engineer)! It was easier than I expected, actually.

Instructions:
http://www.rangefinderforum.com/forums/showthread.php?t=90468
http://www.rangefinderforum.com/forums/showthread.php?t=8497

...
Tools:
Remove outer ring: http://www.generaltools.com/Products/Metric-and-English-Vernier-Caliper__722.aspx
Remove front lens unit (grind down the tips w/Dremel tool): http://www.generaltools.com/Products/Long-Needle-Nose-Pliers__905.aspx
Dividers for use on spanner rings (grind down tips to fit):
http://www.amazon.com/Inside-Outsid...3?ie=UTF8&s=home-garden&qid=1302703485&sr=8-3

Thanks, that's very helpful. Sadly, I'd spend as much on tools and cleaning liquid as I've paid for the camera.


I have contacted the seller, as the stuck aperture blades were not mentioned in the article description.

 

[ka1axy]

Now that I am home, I have tried the actual camera. I experimented and found that the aperture varies with ring setting whenever the shutter is cocked.
- set aperture to 1.7
- set shutter to any speed
- activate winding lever (cocking shutter)
- turn aperture ring and watch the blades open and close

 

[ronnies]

I looked at mine last night and found the following.

With the shutter cocked I can open and close the aperture as normal. Once I've fired the shutter but not yet wound on, I can close the aperture down but not open it up. When I wind on the aperture goes back to where it's set.

Ronnie

 

[FTography]

So, after all, I got a near full refund of what I had paid.
Sending the camera back to the seller would've been more expensive than the total price.
I don't believe I can have the camera fixed or fix it myself for what I got back, though.

At least I got some of my money back, but I would definitely have preferred a working Canonet...

 

[Frontman]

Canonets are usually simple and reliable cameras, but they are a little difficult for those who are not used to them. I sell a lot of Canonets on eBay, and from time to time get complaints about the shutters not working, or that the aperture blades don't move. In most cses the shutter doesn't work because the aperture ring is set to A, and the shutter speed is set too high or too low for a correct exposure, so the camera will not fire. And, as mentioned in the thread, the aperture only moves when the shutter is tripped.

But, with Canonets, the aperture and shutter blades are sometimes prone to sticking. The normal cure is to remove the rear element (the front element is hard to remove without a special tool) and clean blades with Ronsonal or naphtha applied with a q-tip.