Dave Jenkins
Loose Canon
I inherited an Olympus OM10 that I had originally given my dad in 1981. It seems to work okay, but the KS76 batteries appeared to be weak.
I couldn't find an exact match locally, so I replaced them with a pair of A76 alkalines. The meter now appears to read for a 1½--2 stops overexposure.
What batteries should I get, or what alterations/adaptations do I need to make to get reasonably accurate readings?
The camera has the FC manual exposure plug-in, so I could carry a separate meter, but I'd like to avoid that if possible.
I couldn't find an exact match locally, so I replaced them with a pair of A76 alkalines. The meter now appears to read for a 1½--2 stops overexposure.
What batteries should I get, or what alterations/adaptations do I need to make to get reasonably accurate readings?
The camera has the FC manual exposure plug-in, so I could carry a separate meter, but I'd like to avoid that if possible.
Muggins
Junk magnet
Dave,
Not sure whether US and UK battery sizes correspond, so don't know how helpful this will be. However my OM10 manual recommends using LR44s - despite most users swearing that you have to use SR44s (silver rather than lithium) because of the flatter discharge curve. In practice, you'll need to shoot a lot of film to flatten them!
Any help?
Adrian
Not sure whether US and UK battery sizes correspond, so don't know how helpful this will be. However my OM10 manual recommends using LR44s - despite most users swearing that you have to use SR44s (silver rather than lithium) because of the flatter discharge curve. In practice, you'll need to shoot a lot of film to flatten them!
Any help?
Adrian
jesse1dog
Light Catcher
Those are the batteries I use too.
jesse
jesse
John Hermanson
Well-known
OM-10 (along with OM-G, OM-20) do not require silver oxides. You CAN use them (they are longer lasting) but any of these will do: A76, LR44, 357, SR44W, G-13, MS76, KS76, 303, S76. John
Dave Jenkins
Loose Canon
Thanks, guys. The package the batteries came in says A76/LR44, so they must be the right ones. But the camera still overexposes!:bang:
Muggins
Junk magnet
Are you simply checking the shutter time against the meter indication, or are you actually taking photos to check?
The reason I ask is that the OM10 has a meter that gives the indication in the viewfinder, and a second one that reads off the film plane, and calculates the exposure off of that (at least, that's how I understand it). If you don't have a film in, it will not read correctly and I'm fairly sure - it's a while since I've got mine out - that it will appear to overexpose compared to the visible meter.
It is possible it's faulty - I've got an OM10 body that perpetually over-reads by about a stop - but I'd check with a film in first.
Adrian
The reason I ask is that the OM10 has a meter that gives the indication in the viewfinder, and a second one that reads off the film plane, and calculates the exposure off of that (at least, that's how I understand it). If you don't have a film in, it will not read correctly and I'm fairly sure - it's a while since I've got mine out - that it will appear to overexpose compared to the visible meter.
It is possible it's faulty - I've got an OM10 body that perpetually over-reads by about a stop - but I'd check with a film in first.
Adrian
Dave Jenkins
Loose Canon
That's a good point, but if I want to use it in manual mode, I will have to rely on the meter in the viewfinder. Maybe I could work out a compensation factor. But, as you say, I will probably need to shoot some (slide) film to find out just how much compensation.
kuzano
Veteran
It's the voltage curve
It's the voltage curve
Use the alkalines. They will over expose for a month or so. Then for the next month or two, they will expose properly. Then after about four months they will under-expose.
It's the nature of alkaline to weaken steadily as current is drawn out of them. The drop in voltage curve is relatively fast with Alkalines, while silver oxides tend to expose correctly for the duration of their power output, and then die a relatively fast death.
The alkaline battery people were quite pleased with this phenomena, and then the Sony Walkmans and other hand held recording devices came along and made their world "gravy".
So yes, use alkalines , but meter manually.
It's the voltage curve
Use the alkalines. They will over expose for a month or so. Then for the next month or two, they will expose properly. Then after about four months they will under-expose.
It's the nature of alkaline to weaken steadily as current is drawn out of them. The drop in voltage curve is relatively fast with Alkalines, while silver oxides tend to expose correctly for the duration of their power output, and then die a relatively fast death.
The alkaline battery people were quite pleased with this phenomena, and then the Sony Walkmans and other hand held recording devices came along and made their world "gravy".
So yes, use alkalines , but meter manually.
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sig
Well-known
This is not true, if the user manual states that you can use alkaline you can use it. The camera will have some gadget to handle the drop in voltage.
Muggins
Junk magnet
Thw two should coincide fairly well - certainly close enough for jazz - if all is well. It will just seem that the film plane meter is running differently at the moment because it's not currently metering off a film, but the pressure plate instead which is darker and that tiny bit further away. I don't quite understand how exactly it works to make the two meters coincide, but it must do or the OM10 wouldn't have lasted!
Adrian
John Hermanson
Well-known
If your negatives are WAY over exposed, it's a common complaint with the OM-10. Oil on the magnet commonly causes this, it is VERY hard to fix properly. If you are firing the shutter with a lens attached, with it set to auto, point it at a bright light first. It is best to have film loaded or test card in place as auto speeds are read off the first curtain / film plane. One way to test your 10 for oily magnet: cock shutter, set to high ASA, remove lens, hold camera up to very bight bulb (like 100W). Fire shutter and listen to sound. Sound should be one "ker-click" sound. If you hear click (mirror up, shutter open), then a fraction of a second later a separate click of shutter closing/mirror coming down , then you probably have oil on the magnet. John
John Hermanson
Well-known
The meter reading is read off the focus screen by a single CDS cell. Auto speed is read off the curtain / film by silicon blue cell in the floor of the mirror box. The camera is calibrated in a specific order on a known light source so everything matches. John
Muggins
Junk magnet
Thanks John - I'd never actually stopped to think about how the two meters matched until I was posting one of my messages above...
Adrian
Adrian