How long do selenium photocells last?

[snegron]

Any idea on how long selenium photocells found in handheld light meters last? Are there any signs to look out for to know when the meters are reaching the end of their life?

 

[Roger Hicks]

Any idea on how long selenium photocells found in handheld light meters last? Are there any signs to look out for to know when the meters are reaching the end of their life?

Up to 50 years, sometimes significantly more, depending on manufacturing quality and storage (especially exposure to light). Sometimes 5 years or less, ditto.

This is based on 40+ years' experience.

 

[Dan Fromm]

Snegron, what are you getting at? Is this one of your "I know the answer but want to get people thinking" questions or are you contemplating buying one?

If the latter, do some searching (a hint is all you get this time) for Quality Light Metric. After you know what you have in mind to get, call QLM and talk things over with George.

 

[AgX]

In case of need, this company offers custom cut, contacted selenium cells:

http://www.megatron.co.uk/homepage.html

 

[Whiteymorange]

When I had an early Retina SLR CLA'ed by S.K.Grimes a few years ago, they checked the meter for me. They were really surprised the old selenium cell was still accurate over all of its range. They said to be wary of low-light accuracy going first. It will be OK in daylight but to check it often against another, newer meter in low light. I have lots of selenium meters that are NOT accurate.

Thus warned, I have never bothered to check it except in the film I actually shoot. Seems fine by me, but I'm a member of the "sort of f/63" club, and I have scads of bad photos to prove it.

 

[snegron]

Snegron, what are you getting at? Is this one of your "I know the answer but want to get people thinking" questions or are you contemplating buying one?

If the latter, do some searching (a hint is all you get this time) for Quality Light Metric. After you know what you have in mind to get, call QLM and talk things over with George.

Dan, Dan, Danny, Dan, always supecting I'm up to something! :rolleyes:

Ok, I'll humor you (mostly because I have some extra time before my microwave popcorn is done).

1. I plan on purchasing a fully manual, meterless rangefinder in the near future (not decided yet between an old Leica screwmount or an old Leica M3).

2. I would like to get a meter that won't cost more that the old camera I plan to buy.

3. I did some very brief research and have narrowed it down to a Sekonic L-398 Studio Delux III - Analog Incident and Reflected Light Meter. I read its specs and it indicated that it was powered by selenium photocells. No batteries. I find this too good to be true. There must be a catch.

4. If this meter does what it advertises, then I will buy it in a heartbeat. But (and here goes the reason for this post), how long do those selenium photocells last? I would hate to spend money on something that doesn't work or won't last very long. Gee, I should ask my buddies here at APUG who have probably owned this type of meter and have way, way, way much more experience than I do! Hence, the post. :rolleyes:

5. There are so many alternatives on the market today, but this "battery-less" meter seems very appealing. Especially since I enjoy the thought of using fully manual equipment. I would find it very satisfying to go out on the weekend with the wife and kids and only a very small, mechanical rangefinder, several rolls of film, and a reliable eco-friendly light meter. I don't find anything mysterious, menacing, or anti-analog about this.

6. Popcorn is ready. Gotta go.

p.s. Thanks for the QLM tip!

 

[snegron]

Up to 50 years, sometimes significantly more, depending on manufacturing quality and storage (especially exposure to light). Sometimes 5 years or less, ditto.

This is based on 40+ years' experience.

As far as storage goes, will heat affect the meter in a negative way? I live in Florida and it is extremely hot here all the time. I spend most of my time indoors, (as will the meter and my equipment) but I shoot 90% of the time outdoors. Temperatures here are usually in the high 90's (farenheit) and it is very, very bright most of the time. I try to shoot when the sun is setting, so the light varies (sunny 16 rule is not a reliable method for an amateur like me).

 

[snegron]

When I had an early Retina SLR CLA'ed by S.K.Grimes a few years ago, they checked the meter for me. They were really surprised the old selenium cell was still accurate over all of its range. They said to be wary of low-light accuracy going first. It will be OK in daylight but to check it often against another, newer meter in low light. I have lots of selenium meters that are NOT accurate.

Thus warned, I have never bothered to check it except in the film I actually shoot. Seems fine by me, but I'm a member of the "sort of f/63" club, and I have scads of bad photos to prove it.

That is why I am curious about this type of meter! I have seen many old CDS type meters (I have a CDS prism on an old Mamiya 645, another on my RB67, and another on a Nikon F- the Ftn Photomic Prism). My CDS prisms are all still very accurate, but I have read that they die after a few years.

My question is that if selenium photocell-type meters are so reliable and long lasting, why don't all cameras have this type of metering built in? With the advances in technology I'm sure that some engineer can come up with a super sensitive circuit board that can operate a camera using these cells. Remember the solar powered 35mm Ricoh?

There has to be a reason why these meters are not as popular as their battery powered counterparts.

 

[snegron]

In case of need, this company offers custom cut, contacted selenium cells:

http://www.megatron.co.uk/homepage.html

Thanks for the link!

 

[David A. Goldfarb]

My question is that if selenium photocell-type meters are so reliable and long lasting, why don't all cameras have this type of metering built in? With the advances in technology I'm sure that some engineer can come up with a super sensitive circuit board that can operate a camera using these cells. Remember the solar powered 35mm Ricoh?

There has to be a reason why these meters are not as popular as their battery powered counterparts.

In good light they're only accurate to about plus or minus a half stop at best, and they aren't particularly accurate in low light at all. With experience and practice, you can be at least that accurate without a meter.

 

[winger]

I can't say it'll work forever, but my great-grandfather's Weston Master II still matches what I get on my Sekonic. It might even be easier to use - less buttons.
Does amount of use affect the lifespan? 'cause my g-gdad's has been in the dark most of the last 30 years.

 

[snegron]

In good light they're only accurate to about plus or minus a half stop at best, and they aren't particularly accurate in low light at all. With experience and practice, you can be at least that accurate without a meter.

I guess that explains it then! I'm assuming that as time goes by the cells become less sensitive to light and probably give inaccurate readings. On the flip side though, I wonder then why they are still being manufactured? The Sekonik L-398 Studio Delux III that I was looking into is the latest model in the series of this type of meter. The ads say that it has an "amporphous silicon light sensor that meets today's industry standards", whatever that means.

 

[David H. Bebbington]

In good light they're only accurate to about plus or minus a half stop at best, and they aren't particularly accurate in low light at all. With experience and practice, you can be at least that accurate without a meter.

Pardon me for asking, but on what is this statement based? I own around 8 Weston meters, a Master II, a Master III, a Master IV, several Master Vs and Euromasters, and regularly cross-check these against each other and against built-in meters (Leica R3 and R8, Nikon FM3a) and also a Sekonic L308 and a Gossen Digiflash. I do this usually in my office, takng one measurement of my desk lit by a 40 W desklamp, and one of the exterior out of the window. I find all meters agree 100% (if one doesn't, it goes to the repairman). I used Weston Masters for years in the 1960s and 1970s for tungsten-lit studio still-life photography and got spot-on accuracy every time!

 

[craigclu]

I guess that explains it then! I'm assuming that as time goes by the cells become less sensitive to light and probably give inaccurate readings. On the flip side though, I wonder then why they are still being manufactured? The Sekonik L-398 Studio Delux III that I was looking into is the latest model in the series of this type of meter. The ads say that it has an "amporphous silicon light sensor that meets today's industry standards", whatever that means.

I bought an L-398 back in 1975 after borrowing a friend's to have in the hospital delivery room for the birth of our daughter. It still agrees with my Minolta Spot-F and Sekonic L-718 and has served me well all of these years but hasn't been used too much in recent years. When I was using it more, I purchased the slide kit. The kit didn't get much use but it functioned quite well when I took the time to use it.

 

[DWThomas]

an "amporphous silicon light sensor that meets today's industry standards", whatever that means

It has a whif of marketspeak about it, but selenium cells are not silicon. It sounds like they are producing the same/similar meter with a new, non-selenium sensor. I think in general the selenium compounds used in electrical devices are less stable than silicon devices. "Solid state" rectifiers were selenium back in my youth, they exhibited high leakage and their degradation over time was much worse than the silicon based semiconductor devices that came along later.

DaveT

 

[Andrew Kleinfeld]

long indeed

The cheapest Sekonic, that I bought about 50 years ago when I was around 12, still works fine. And some better Sekonics, the incident studio types, I've bought used, of around the same vintage, still work fine, as do my ancient Westons bought used. On the button, not within a half stop. On the other hand, a Gossen Pilot I bought I think in the '80's is dead. (But so is a Gossen silicon blue cell I bought around 1990. Are Sekonics better than Gossens? Is it just chance? I don't know.

Any idea on how long selenium photocells found in handheld light meters last? Are there any signs to look out for to know when the meters are reaching the end of their life?

 

[Steve Smith]

I own around 8 Weston meters, a Master II, a Master III, a Master IV, several Master Vs and Euromasters......

I find all meters agree 100% (if one doesn't, it goes to the repairman).

I worked with someone who used to work at Sangamo Weston and he once told me that Weston meters could all be out by up to 1.5 stops when new. I found this very hard to believe considering that they were once the standard by which all other meters were judged (at least in the UK). I don't think professionals or most amateurs would have put up with such inaccuracies.

My father used to have a new Weston meter every year. He worked as a central heating system designer by day and a wedding photographer at weekends. In his central heating designing role he used Sangamo Weston timers and received regular visits from the Weston representative. Each year he would bring my father a new meter and take the old one back!


Steve.

 

[Roger Hicks]

As far as storage goes, will heat affect the meter in a negative way?

As far as I know, light is the sole problem, and to get the life down to 5 years you'd need to leave the meter in a south-facing shop window, with the cell uncovered, whenever you weren't using it. Normal use, even in very bright conditions, will not 'wear out' the cell (= loss of sensitivity). A well-made selenium cell meter should last many decades if bought from new and kept in its case when not in use -- longer than most of us are likely to live.

Nor is accuracy an issue, again, with a well made meter. At one time I had three Weston III meters that all agreed within 1/6 stop of each other and gave excellent exposures. As often as not, any two meters of any kind -- Se, CdS, silicon blue -- will disagree by 1/3 stop.

The sole disadvantage of Se meters is that they are not very sensitive. They're fine in normal room lighting, but anything less is likely to defeat them. That was the big selling point of the LunaSix/LunaPro in the days when the Weston Master mas king -- but CdS meters suffer from 'lag' or 'memory' and can take as much as half a minute to climb to their full reading or if they've just been used in bright light) to fall to their correct reading. That's why CdS was replaced by silicon blue.

 

[David H. Bebbington]

As far as I know, light is the sole problem ...

I thought so, too, but doing some research inspired by this and the other thread, I find that this gentleman:
http://mattdentonphoto.com/cameras/repairtips.html
and others feel that humidity plays a part, too. This would explain the variation in behavior between selenium cells of around the same age which have been protected equally from light - possibly devices like Weston meters and Rolleiflex cameras have a better seal against moisture?

 

[Dan Fromm]

<snip>

Ok, I'll humor you (mostly because I have some extra time before my microwave popcorn is done).

<another snip>

3. I did some very brief research and have narrowed it down to a Sekonic L-398 Studio Delux III - Analog Incident and Reflected Light Meter. I read its specs and it indicated that it was powered by selenium photocells. No batteries. I find this too good to be true. There must be a catch.

4. If this meter does what it advertises, then I will buy it in a heartbeat. But (and here goes the reason for this post), how long do those selenium photocells last? I would hate to spend money on something that doesn't work or won't last very long. Gee, I should ask my buddies here at APUG who have probably owned this type of meter and have way, way, way much more experience than I do! Hence, the post. :rolleyes:

5. There are so many alternatives on the market today, but this "battery-less" meter seems very appealing. Especially since I enjoy the thought of using fully manual equipment. I would find it very satisfying to go out on the weekend with the wife and kids and only a very small, mechanical rangefinder, several rolls of film, and a reliable eco-friendly light meter. I don't find anything mysterious, menacing, or anti-analog about this.

Thanks for humoring me. As usual, you worry too much. Sekonics and their ancestors Norwood Directors are pretty robust.

You should be aware that one of Murphy's laws is that all exposure meters bought used need to be overhauled.

But since your heart is set on an L-398s, stop whining and buy a new one. B&H offers them for $179 plus postage. That fits your "costs no more than the camera and a lens" constraint. With service, a used one from eBay (look at completed auctions, I just found 20) will cost nearly as much, possibly more.

If you don't reach your weight reduction goal, the meter will probably outlive you. And if you do it still might.

Cheers,

Dan

 

[Roger Hicks]

I thought so, too...

Dear David,

Yes, but I'm slightly suspicious: "he's heard". Yes, I've heard it too, but I am far from convinced. This was what I meant about manufacturing quality/well made. I'm sure that humidity can ruin a cheap or poorly made meter, but this could be for a number of reasons including corrosion of the contacts. Assuming good build quality (which admittedly is quite an assumption) I suspect it is light and nothing else.

There were a couple of other things on his site that jumped out at me too, such as the statement that CdS has been the standard since the 60s. As far as I am aware, CdS has been almost completely dropped because of lag/memory problems, and replaced with other light-sensitive solid state cells, usually (?all) silicon-based.

Cheers,

Roger

 

[snegron]

While doing some further reading of the specifications of the Sekonic L-398 on the B&H site, I found out that its EV range is only from 4 to 17. There were other battery powered meters available that appeared to have a wider EV range (the Gossen Digisix lists an EV range from 0 to +18). I am begining to wonder if it is a better idea to spend the extra $45.00 and get the battery powered Gossen instead of the L-398 in view of the fact that I will have the option of metering in broader EV ranges.

 

[Roger Hicks]

I am begining to wonder if it is a better idea to spend the extra $45.00 and get the battery powered Gossen instead of the L-398 in view of the fact that I will have the option of metering in broader EV ranges.

I would, for exactly the reason you give. I've had one of the baby digital Gossens since it came out, well over 10 years ago. If it's left unused for many months at a time, the electrical contacts on the buttons stop working, but two or three smart pressures get them working again.

 

[David H. Bebbington]

... I am begining to wonder if it is a better idea to spend the extra $45.00 and get the battery powered Gossen instead of the L-398 in view of the fact that I will have the option of metering in broader EV ranges.

The Gossen Digisix comes with a very neat screw-on foot so that you can mount it in an accessory shoe - handy if you're thinking of buying a meterless Leica!

 

[David A. Goldfarb]

Another fan of the Digisix here. I'd probably buy a Digiflash, if I were buying one today.

For a long while, while it seemed that all my watches needed repair or a battery or a new band or something, I was carrying my Digisix as a pocket watch. It did require more frequent cleaning that way, but it wasn't too difficult. A little canned air to blow it out and contact cleaner on the switch contacts keeps everything working properly.