Minolta 7s Metering

[M4cr0s]

Hi all!

My first post here on this great forum, and it's a bit long and tedious too.. Hope I didn't post in the wrong category at least 😉

I recently aquired a 7s through the 'bay because I want to play a bit around with film, and because rangefinders intrigue me. The seller didn't know squat about cameras (why is it that like 90 % of the peeps selling cameras on Ebay doesn't seem to know anything about cameras, are they all the same guy under different nicks or something?) but I took a chance and got it for little more than 10$, thinking that if it didn't work it'd at least look good on the shelf 😉

The camera is in fact close to what I'd call mint, except of two minor wear marks on the extreme edges of the film-hatch at the back. The included half-case on the other hand looks like it's gone through a couple of wars 😉 Shutter works smoothly, but I can't really test the speeds, except by visual. Both the aperture blades and the shutter's move very nicely. Also the self-timer works. Viewfinder is a little bit dim, but appears pretty clean. The lens is completely scratch-free, a few tiny specks of dust inside, only seen if you use a flashlight. Actually my Nikon and Tammy zoom-lenses looked worse fresh from the factory, can't understand why they don't assemble lenses in a dust-free enviroment.. On the other hand, zooms push and pull air in and out of the lens/sensor chamber regardless, so maybe it doesn't matter. The meter works/responds, as I'm hearing-impaired I actually had a pack of old 675s (expired back in july 2008, something that might affect things) lying around and while these don't make a perfect fit, they do seem to at least power the meter.

Now, I've primarly worked with DSLRs and digi compacts and I haven't got much experience with older cameras and their metering, except some fidling in my youth with my dad's old Petri FT and the needle-system it had. I have no idea of how the meter of the 7s in fact works and in what way it differs from "modern" in-camera metering. It can't really be comparable to any modern metering technologies such as spot, CW or matrix, since these, as far as I understand, measures the light bouncing off whatever you try to meter. The 7s on the other hand, has an "eye" that measures the light hitting it, no?

When trying to match meter readings compared to my DSLR, the 7s often suggest quite different exposures (up to 1-3 full stop difference) and that is a bit worrying. I know different metering systems give different results and that there's normally a certain amount of technique/know-how about the metering system involved in making correct exposures. Also, as far as I understand, expecially color neg film have quite a bit of latitude and is a bit more forgiving than digital. Should I worry about the metering differences, or just go out shooting. Alternatively, just go sunny 16?

I hope someone has the patience to answer a rangefinder/film n00b and enlight me a little bit. If you have tips or tricks concerning exposure with these neat little machines I'd be very happy to receive them.

/Mac

 

[Chriscrawfordphoto]

"I don't know anything about cameras" is ebay code for "This camera is a broken piece of crap, and i'm a dishonest ******* who is looking for someone to cheat"

 

[M4cr0s]

"I don't know anything about cameras" is ebay code for "This camera is a broken piece of crap, and i'm a dishonest ******* who is looking for someone to cheat"

I suspect you be partially correct on the issue of Ebay sellers 😉 I took a calculated risk on this one because the seller provided a large number of pictures of this spesific camera and it looked pretty good. On the other hand "it clicks when pulling the film thingy and pressing the shoot button" hardly constitutes a thorough evaluation of a cameras functional condition.

Got any input on the metering? 😉

 

[Chriscrawfordphoto]

The 7s meter is a reflected light meter. the little lens for the meter cell gives it about the same angle of view as the taking lens on the camera, so it is basically a fullframe averaging meter. Keep in mind that the camera was designed for Mercury batteries, which have been banned to protect the environment, and modern alkaline and silver oxide batteries will not work in it. Some companies make an Alkaline that is the same size and shape as the original Mercury cell, but its voltage is different and so the meter will be innaccurate. You can have the meter circuit modified to adjust the voltage of modern batteries to match that of Mercury cells, or you can buy an MR-9 adapter (costs about $40). It is a holder for a small silver oxide battery that includes an electronic diode that knocks the modern battery's 1.55v output down to the 1.35 volt the meter requires. Or, you could use Wein Cells, which are Zinc-air hearing aid batteries adapted to fit your camera. They produce the right voltage but do not last long, and are kinda expensive.

I have a 7s that I only used once because the first time i used it I realized the rangefinder was not accurate, everything was focused wrong, and I didn't have the $$ to get it fixed. I didn't bother with the built in meter, just used a handheld meter.

 

[camera.bear]

Mac,

If your serious about using the Hi-Matic 7s, get a Wein cell and try it out. I was successful with a one in my Hi-Matic 9. I have also used the 1.5v silver oxides in this and other of my Hi-Matic rangefinders with good results. I was shooting color negative film and it has a wide latitude for exposure. Slide film requires more accurate exposure and might be a problem with the 1.5v silver oxides. Good Luck and enjoy your camera; I have had a good time with mine and these give very nice results.

http://www.flickr.com/photos/camerabear/sets/72157617749812081/

 

[M4cr0s]

The 7s meter is a reflected light meter. the little lens for the meter cell gives it about the same angle of view as the taking lens on the camera, so it is basically a fullframe averaging meter.

Thanks, that helps my understanding a bit 🙂

Keep in mind that the camera was designed for Mercury batteries, which have been banned to protect the environment, and modern alkaline and silver oxide batteries will not work in it. Some companies make an Alkaline that is the same size and shape as the original Mercury cell, but its voltage is different and so the meter will be innaccurate. You can have the meter circuit modified to adjust the voltage of modern batteries to match that of Mercury cells, or you can buy an MR-9 adapter (costs about $40). It is a holder for a small silver oxide battery that includes an electronic diode that knocks the modern battery's 1.55v output down to the 1.35 volt the meter requires. Or, you could use Wein Cells, which are Zinc-air hearing aid batteries adapted to fit your camera. They produce the right voltage but do not last long, and are kinda expensive.

Yeah, I read up on the possible replacements for those batteries oh so common in the 60s and 70s rangefinders and SLRs before I started looking for a rangefinder from this era to buy. As I said in my initial post I had some 675 hearing aid batteries lying about and they are the right voltage too. I have numerous (cheap) sources for these so I plan to use them. Also, the 7s has two holes in the battery cap by default it seems, should take care of the air the zinc-air batteries need.

I have a 7s that I only used once because the first time i used it I realized the rangefinder was not accurate, everything was focused wrong, and I didn't have the $$ to get it fixed. I didn't bother with the built in meter, just used a handheld meter.

I guess I won't know if the rangefinder is sort of ok before I've shot a roll. It's not totaly off compared to the distance scale on the lens at least, yet there could of course always be minor irregularities.

/Mac

 

[M4cr0s]

Mac,

If your serious about using the Hi-Matic 7s, get a Wein cell and try it out. I was successful with a one in my Hi-Matic 9. I have also used the 1.5v silver oxides in this and other of my Hi-Matic rangefinders with good results. I was shooting color negative film and it has a wide latitude for exposure. Slide film requires more accurate exposure and might be a problem with the 1.5v silver oxides. Good Luck and enjoy your camera; I have had a good time with mine and these give very nice results.

http://www.flickr.com/photos/camerabear/sets/72157617749812081/

I understand from my searching, that the wein cell is just a overpriced 675 hearing aid battery with some casing to make it fit perfectly and emulate the physical size of the PX625/PX13. I see no reason to get these if the hearing aid batteries work. I have decades of experience with hearing aid batteries and know they are very dependable and keep putting out a stable voltage almost to their last breath. Also, they can be picked up in 6-packs for a few bucks and hardly reacts to temperature changes and can be stored almost everywhere (jacket pockets, car dashboards etc).

I won't be shooting slides, mostly color negs and probably some chromogenic B&W in time. I guess I can take the risk to err a little bit exposurewise. Hope the weather is sort of ok tomorrow, looking forward to burn through my first roll 🙂 I'll try a roll of some ISO200 Superia and get it developed at the lokal cam store imediately.

/Mac

 

[Wayno]

My 7s meter is pretty accurate with an alkaline 625. The meter is actually more sophisticated than most similar cameras from the era - Minolta called it "CLC" (Contast Light Compensating) metering. As I recall the meter takes two readings (top and bottom) and must place more weight on the lower value to compensate for bright sky, etc. Having said that, like all older onboard meters it's best to try to take a reading close to your main subject or to point it down towards the ground to exclude most of the sky when you're taking a reading. This may be difficult if you're using Auto mode, but you could compensate with the ASA setting if you find that it's overexposing consistently. As the meter is always on, I try to keep a lens cap on the camera to prevent battery drain. You can turn it off with the ASA control, but that's a pain to do all of the time.

I hope you enjoy your 7s - the Rokkor lens is fantastic.

 

[ebolton]

I have a 7s I got with an alkaline cell in it about a year ago. I know it is off a bit because of the voltage, but mine is easily close enough to be correctible during scanning of the film. I run a hearing aid battery in my Canonet, but in the 7s I just live with the alkaline battery.

I use the 7s in manual mode, and the EV readout in the viewfinder in manual is pretty instructive. I'd probably use the 7s more, but I find the ergonomics a little tough, especially the closeness of the shutter and aperature rings.

It's a nice camera.

 

[Sonnar Brian]

If the meter disagrees with the SLR at the high end and low-end of the sensitivity scale, the CDS "electric Eye" could be going. It will lose sensitivity at the end of its metering range. Set up a "grey-scale" test, like a flat piece of cardboard. Illuminate it, and then meter it using the SLR and the Minolta. Check the metering range across the ASA settings on the camera. That will change the aperture in front of the CDS cell, dimming the light that hits the cell. The readings between the two cameras should be the same across the scale. If the variation is a "constant", you can compensate with the ASA setting. If it is varies across the range, the cell is going and you should use a hand-meter.

 

[M4cr0s]

If the meter disagrees with the SLR at the high end and low-end of the sensitivity scale, the CDS "electric Eye" could be going. It will lose sensitivity at the end of its metering range. Set up a "grey-scale" test, like a flat piece of cardboard. Illuminate it, and then meter it using the SLR and the Minolta. Check the metering range across the ASA settings on the camera. That will change the aperture in front of the CDS cell, dimming the light that hits the cell. The readings between the two cameras should be the same across the scale. If the variation is a "constant", you can compensate with the ASA setting. If it is varies across the range, the cell is going and you should use a hand-meter.

Doing a semi-scientific test is the obvious thing to do, yet my mangled brains never got so far in its chain of thought 😱 I'll have a try tomorrow and make me some notes, that + some real-life shooting should provide me with the answers. The meter being somewhat "off" isn't much of an issue, I'm obviously mostly concerned with inconsistency. Have you got any idea of how long the lifespan of such CDS cells tend to be, and which factors make them degrade? For instance, will turning the meter off with the off-setting on the ASA-scale switch, or using a lens cap as much as possible have a positive/negative effect?

Thank you for taking your time to answer!

/Mac

 

[M4cr0s]

My 7s meter is pretty accurate with an alkaline 625. The meter is actually more sophisticated than most similar cameras from the era - Minolta called it "CLC" (Contast Light Compensating) metering. As I recall the meter takes two readings (top and bottom) and must place more weight on the lower value to compensate for bright sky, etc. Having said that, like all older onboard meters it's best to try to take a reading close to your main subject or to point it down towards the ground to exclude most of the sky when you're taking a reading. This may be difficult if you're using Auto mode, but you could compensate with the ASA setting if you find that it's overexposing consistently. As the meter is always on, I try to keep a lens cap on the camera to prevent battery drain. You can turn it off with the ASA control, but that's a pain to do all of the time.

I hope you enjoy your 7s - the Rokkor lens is fantastic.

Hmm. this is good information. Quite interesting take on the metering in fact. I landed on the 7s because I understood from various sources that it has a pretty good lens, except being prone to flare. It will be interesting to see how the pictures turn out in terms of resolution and contrast with modern film 🙂

The only things so far I've noticed from furter physical examination of the cam, is the slight tendency of the lens to wobble and that the glass in front of the viewfinder/rangefinder seems a bit flimsy/loose. I definitely need to learn to pick up the camera in a way so that I don't push it in with my fingers.

As a side-note I'm getting a second vintage camera in the mail today, a '73 or so Petri FT1000 (evil?) SLR in confirmed working order with three lenses. Bought this one purely from nostalgic reasons as my dad had a Petri SLR from this period. I suspect people will be looking pretty weird at me when I go around with two "antiques" shooting film....the missus is already giving me "circus freak" looks and shakes her head 😉

/Mac

 

[Wayno]

Yep, the lens is really sharp. This is a crappy print scan from the first roll I ever took with mine, but I think you can see that even wide open it performs well:



The lens wobble seems to be pretty common with the Hi-matics, but probably doesn't have any noticeable effect. I managed to fix mine when I had it dismantled to service the shutter, but I can't remember how I did it now (that was many years ago).

 

[M4cr0s]

Yep, the lens is really sharp. This is a crappy print scan from the first roll I ever took with mine, but I think you can see that even wide open it performs well:



The lens wobble seems to be pretty common with the Hi-matics, but probably doesn't have any noticeable effect. I managed to fix mine when I had it dismantled to service the shutter, but I can't remember how I did it now (that was many years ago).

That pic looks pretty good, not at all "old camera" 🙂 I just got back after a weekend with a mate (whom could not quite believe the camera was made back in 66, considering it's condition) and I got the time to shoot a roll with the 7s. I am a little conspicious of the light seals around the film door, I made a temporary fix to the one at the hinge end of the door, but it might leak other places too. At least tomorrow I'll get the roll developed and I'll know more about how it works. Looking forward to see the results of my (probably) clumsily attempts with a manual focus and all that kind of camera. Metering does not seem very much off in practical use, if anything, generally very close to the sunny 16 I'd choose for a particular scene.

/Mac

 

[Sonnar Brian]

> Have you got any idea of how long the lifespan of such CDS cells tend to be, and which
>factors make them degrade?

It's almost a function of the life it lead. I have 40 year old CDS cells that are VERY accurate, from meters that were kept in cases. If the camera had the lens cap on, was in a case, saw casual/moderate use, it probably fairs better than one left in a camera shop window as a Display.

Best to test it. Turning the power off does not affect it.

 

[Trius]

I had a 7s which I quite liked except I didn't care for the size (a bit larger than I prefer, but nothing I couldn't have lived with) and the viewfinder seemed a bit odd to me. And I had more fixed lens RFs than I needed. 😀

The meter on mine was very accurate. Along with the quality of the lens (yes, mine wobbled,) it was one of the things I liked very much about the 7s.
For the battery, I also used zinc-air 675s. For a better fit I used a #9 o-ring around it, easily acquired at a hardware store for pennies. IMO the Wein cells are no better and a waste of the extra money. They may last a tiny bit longer, but 675 hearing aid batteries are cheap and easily available.

 

[Armoured]

When working, awesome meter and good lens/colour

When working, awesome meter and good lens/colour

Coincidentally, I just dug up my 7SII from storage at a friend's and ran a roll through it (warning: no merit beyond test). Stuck a hearing aid battery in it and was astounded to see perfect exposures throughout (although one or two shot straight into light overwhelmed the lens and blew out the contrast; easily fixed). Note these are just dipped and scanned at the local drugstore. When I say astounded, not so much by results but that 15 years or so of neglect didn't seem to hurt it.

It's that time of year where the greens are surreal, and the old Himatic did a better job of hitting it than my digitals.

(Oh, and front lens has a tiny bit of wobble, never seems to have any effect).

 

[M4cr0s]

I finaly got my first roll from the 7s back today.

The camera do indeed seem to work just fine! 🙂 The lens appears to be very good, pretty darn good sharpness in the center, corners a tad softer. Focus is spot on, so the rangefinderthingy must be working fine too. Quite a number of the images are slightly on the dark side exposurewise, if this is my error, the film (Superia 200) or the lab I do not know. I think I'll simply try to set the next roll to a notch or two lower ISO than it is marked and see how it fares. The pictures are vivid with good contrast, just as I hoped, and have great detail and considerable dynamic range. All things considered I'm looking forward to do more rolls with the 7s 🙂

/Mac

 

[camera.bear]

I finaly got my first roll from the 7s back today.

The camera do indeed seem to work just fine! 🙂 The lens appears to be very good, pretty darn good sharpness in the center, corners a tad softer. Focus is spot on, so the rangefinderthingy must be working fine too. Quite a number of the images are slightly on the dark side exposurewise, if this is my error, the film (Superia 200) or the lab I do not know. I think I'll simply try to set the next roll to a notch or two lower ISO than it is marked and see how it fares. The pictures are vivid with good contrast, just as I hoped, and have great detail and considerable dynamic range. All things considered I'm looking forward to do more rolls with the 7s 🙂

/Mac

Congrats on the success with your 7s. These cameras are really nice to shoot with and I really enjoy my 9. Do you have any images to share?

 

[uhligfd]

To know whether the lightmeter is off, DO NOT look at the prints; look at the film itself. The film should be about medium dark on average, not near clear like the edge of it is (underexposure), and not nearly black (overexposure) ether, all judged on average.