Canon QL17 + 1.5v battery - adjust ISO or invest in MR9?

Discussion in '35mm Cameras and Accessories' started by darinwc, Feb 19, 2013.

  1. darinwc

    darinwc Subscriber

    Messages:
    2,466
    Joined:
    Dec 14, 2003
    Location:
    Sacramento,
    Shooter:
    Multi Format
    Hello all! I just replaced the seals on a Canon QL17.
    This is the smaller model with the 40mm f1.7, but with the plain QL17 nameplate before they updated to GIII.

    I also cleaned the rangefinder, and wow what a difference that makes! It's like 2x as bright as any other viewfinder ive seen.

    OK, so here is my question.. I was planning to just use a silver-oxide 1.5v battery but I was reading about the MR-9 adapter.
    It reduces the voltage from 1.5v to 1.35. But does it actually have a voltage regulator circut to keep the voltage steady or does it just have a resistor that flatly reduces the voltage?
     
  2. Chan Tran

    Chan Tran Member

    Messages:
    2,393
    Joined:
    May 10, 2006
    Location:
    Aurora, IL
    Shooter:
    35mm
    If I were you I would try the 1.5v battery and see if it's accurate enough. If not I would use the camera without battery as the QL17 can be used without battery.
     
  3. Cold

    Cold Member

    Messages:
    51
    Joined:
    Aug 27, 2012
    Shooter:
    35mm RF
    From what I remember, it's a fairly simple in-line resistor to reduce the voltage, but the silver-oxide batteries have a surprisingly flat discharge voltage anyway, rivaling that of mercury.

    If you're shooting B&W negative, I'm sure you could get results 'close enough for government work' shooting at the rated speed. After a few rolls, if you notice consistent over-exposure that is problematic (I've come to appreciate a touch of overexposure in my negs), a simple adjustment of ISO on camera would probably be sufficient.

    Of course, it's worth noting that eventually, I'm planning on sending in my own QL17 for a CLA soon, at which point, I'll be having the shop convert it for the silver-oxide cells...so take that for what you will. :tongue:
     
  4. madgardener

    madgardener Member

    Messages:
    405
    Joined:
    May 28, 2011
    Location:
    Allentown PA
    Shooter:
    35mm
    Another alternative is to purchase an adapter, and use standard hearing aid cells. They provide almost the exact voltage your camera needs, downside is that they don't last that long. I'm using them in my Konica Autoreflex TC.

    If you do a search on Ebay you can usually find them, or if you are handy you can find plans on the internet to build your own adapters.
     
  5. davidmasek

    davidmasek Member

    Messages:
    31
    Joined:
    Apr 17, 2010
    Location:
    Prague
    Shooter:
    Medium Format
    I thought that the Schottky diode is mostly used to drop the voltage by 0.15V.
     
  6. E. von Hoegh

    E. von Hoegh Member

    Messages:
    3,921
    Joined:
    Sep 14, 2011
    Location:
    Adirondacks
    Shooter:
    Multi Format
    Correct.
     
  7. Fred Aspen

    Fred Aspen Member

    Messages:
    717
    Joined:
    Aug 23, 2006
    Location:
    North-ish-western US
    Shooter:
    Multi Format
    I found the best solution for these cameras that use the old PX625 mercury batteries is to make a quick trip to Costco and go the pharmacy and buy a card with 30 ea. 675 hearing aid batteries. These zinc-air batts are about 1.4v nominally and last a couple of months. The batts on the card don't get activated until you remove the blue foil tab. I believe I paid about $10 for the card. I have been running my old cameras on these batts for 4-5 years now. I think it is the best solution for these old cameras. Yep, you have to change them more often but you don't need an adapter, circuit changes, or recalibration of the light meter circuit.

    If you are really frugal, you can remove the batts from the camera after use, re-install the little blue tab and put them away. This stops the chemical reaction and discharge of the battery. Like I said, I have the original card from 4-5 years ago and still have a few left. I think the card has a 5-6 year 'use by' date on it.

    If your camera is a current hog, take a couple of extras with you when you shoot.

    You simply can't beat this solution!
     
  8. David Lyga

    David Lyga Subscriber

    Messages:
    1,943
    Joined:
    Nov 25, 2007
    Location:
    Philadelphia
    Shooter:
    35mm
    Correct me if I am wrong here but when a 1.5V button cell starts to lose power, doesn't its power drop from 1.5V? Is there really such a big deal between 1.35V and 1.5V? - David Lyga
     
  9. E. von Hoegh

    E. von Hoegh Member

    Messages:
    3,921
    Joined:
    Sep 14, 2011
    Location:
    Adirondacks
    Shooter:
    Multi Format
    It's only a "big deal" if you want an accurate meter.
    Mercury oxide cells were used because of their flat discharge curves. Silver oxide cells also have a very good discharge curve, nearly as flat as mercury cells. Alkaline cells do not have a flat curve, their voltage falls constantly over the life of the cell.

    Hearing aid zinc-air cells are the best low cost solution, a Schottky diode adapter is the deluxe solution as it allows you to use long life silver oxide cells.

    .15v doesn't sound like much, but it is better than 10% of 1.35v and yes it does make an observable difference in readings.
     
    Last edited by a moderator: Feb 19, 2013
  10. nwilkins

    nwilkins Member

    Messages:
    384
    Joined:
    Feb 9, 2012
    Location:
    Nova Scotia,
    Shooter:
    Medium Format
    I am using a non mercury battery in mine and I just found a surface of uniform brightness to take meter readings. I simply adjusted the ISO until the Canonet meter agreed with the meter on my FM2 (around half a stop difference). The AE setting has worked fine since then.
     
  11. Fred Aspen

    Fred Aspen Member

    Messages:
    717
    Joined:
    Aug 23, 2006
    Location:
    North-ish-western US
    Shooter:
    Multi Format
    The only problem with adjusting ISO is that the meter circuitry may not be linear vs. supply voltage. It might now be good in sunny 16 but off when measuring in low light. Most circuits are non-linear but it depends on the camera.
     
  12. Bill Burk

    Bill Burk Subscriber

    Messages:
    5,072
    Joined:
    Feb 9, 2010
    Shooter:
    4x5 Format
    Of course the strength of the QL17 is its manual mechanical shutter that you can use with any meter.
     
  13. nwilkins

    nwilkins Member

    Messages:
    384
    Joined:
    Feb 9, 2012
    Location:
    Nova Scotia,
    Shooter:
    Medium Format
    Very interesting. I should add that although I have had no problems I am using b/w film, where there is quite a bit of margin for error. If the OP is going to be using E6 then maybe the converter is the best answer. Also for what it's worth I find I most often use the camera in manual mode anyway.
     
  14. Sponsored Ad
  15. E. von Hoegh

    E. von Hoegh Member

    Messages:
    3,921
    Joined:
    Sep 14, 2011
    Location:
    Adirondacks
    Shooter:
    Multi Format
    Some meters can be recalibrated to use the silver oxide cells, it's well worth doing if you have such a meter.
     
  16. Cold

    Cold Member

    Messages:
    51
    Joined:
    Aug 27, 2012
    Shooter:
    35mm RF
    Compared to these results, my little Canonet is downright current-ravenous! I can expect maybe 2-5 outings of life from one 675 zinc air cell. I'm guessing/hoping that there's some sort of fouling/shorting/issue with the circuitry that a good CLA will fix, and that I'll get plenty of life from a silver-oxide, once it's been converted.
     
  17. E. von Hoegh

    E. von Hoegh Member

    Messages:
    3,921
    Joined:
    Sep 14, 2011
    Location:
    Adirondacks
    Shooter:
    Multi Format
    Yes, but it's sometimes very handy to have a camera with built-in metering. I've been using #675 hearing aid cells in my Nikkormat, blocking off three of the four airholes makes a huge difference in cell life, they last a year or more for me.
     
  18. Fred Aspen

    Fred Aspen Member

    Messages:
    717
    Joined:
    Aug 23, 2006
    Location:
    North-ish-western US
    Shooter:
    Multi Format
    Now there's a great idea! I haven't given that a shot yet. My concern was that when using two of the cells piggyback, how do you block the holes and still maintain contact between the cells? Perhaps you have solved that issue? I would be most grateful to hear how that is accomplished. Definitely a great idea!
     
  19. E. von Hoegh

    E. von Hoegh Member

    Messages:
    3,921
    Joined:
    Sep 14, 2011
    Location:
    Adirondacks
    Shooter:
    Multi Format
    I fill the holes with glue, then scrape it off the contacting surface. The 'mat takes one cell, the FtN finder for my F as well as my Gossen meters take two cells. You can use O-rings as bushings to keep the cell centered.

    The cell in my camera is still active, I installed it April 2011.
     
  20. mgb74

    mgb74 Subscriber

    Messages:
    3,013
    Joined:
    Jan 24, 2005
    Location:
    Minneapolis,
    Shooter:
    Multi Format
    Do you use a lens cap? As I recall, the meter is always on.
     
  21. Fred Aspen

    Fred Aspen Member

    Messages:
    717
    Joined:
    Aug 23, 2006
    Location:
    North-ish-western US
    Shooter:
    Multi Format
    Thanks for the instructions! I do use the O rings when necessary.
     
  22. E. von Hoegh

    E. von Hoegh Member

    Messages:
    3,921
    Joined:
    Sep 14, 2011
    Location:
    Adirondacks
    Shooter:
    Multi Format
    You're very welcome. Pass it on, I dislike seeing folks ripped of on those Wien cells. :smile:
     
  23. madgardener

    madgardener Member

    Messages:
    405
    Joined:
    May 28, 2011
    Location:
    Allentown PA
    Shooter:
    35mm
    My Konica Autoreflex TC uses 2 batteries, Stacking them blocked the air holes and I didn't get a current. I ended up buying 2 adapters so I can use the hearing aid cells. All the adapter is, is a cleaned out alkaline px13, which leaves a hole for the hearing aid cell. It works very well in my Konica. Why did I buy the adapter? Because I don't want to mess with the chemicals in the battery, it was worth it to me to buy them already cleaned out.
     
  24. nwilkins

    nwilkins Member

    Messages:
    384
    Joined:
    Feb 9, 2012
    Location:
    Nova Scotia,
    Shooter:
    Medium Format
    The meter is only on in auto exposure mode, so moving the aperture ring off the "A" setting should turn it off. At least I think so. I always do this when not using the camera.
     
  25. Cold

    Cold Member

    Messages:
    51
    Joined:
    Aug 27, 2012
    Shooter:
    35mm RF
    This is correct.

    This is where I think mine may have a problem, as the battery appears to be draining in mine regardless of being on "A" or not, capped or not.
     
  26. darinwc

    darinwc Subscriber

    Messages:
    2,466
    Joined:
    Dec 14, 2003
    Location:
    Sacramento,
    Shooter:
    Multi Format
    OK, after using a light bulb to compare my QL17's meter to another QL17, four other SLR's, and five meters.. I am confused.
    I will try again during daylight when I can use a grey card.