Which 35mm SLR screw mount camera (M42) has the biggest, brightest viewfinder and open aperture metering?

runswithsizzers · Oct 26, 2023

... and it would be great if the camera also uses a modern battery.

Recently, I inherited a Pentax Spotmatic SP with a 50mm Super-Takumar f1.4 lens. I was thinking about having it serviced for use, but after looking through the viewfinder and contemplating the reality of stop-down metering, I got to wondering what other screw mount bodies might have better viewfinders and wide open metering? I already have other SLRs with bayonet mounts that I will probably use more than a screw mount camera, so I don't need a "system camera." If I get a screw-mount body, I will need only two lenses for it, a 50mm and a 35mm; hopefully the 35mm will have a maxium aperture of at least f2.8.

As for "big" the manufacturers usually give a viewfinder magnification specification (when used with 50mm lens). And the specs also give a number for field-of-view; that is, what percentage of the final image shows in the viewfinder. When I was shooting slides, this number was important to me, but now that I am shooting mostly b&w negative film, I don't care so much about the field-of-view spec.

As far as I know, there is no objective specification for viewfinder brightness. Subjectively, comparing the brightness of the viewfinders on cameras I have now, listed from best to worst:

Pentax MX = 0.97 magnification, 95% field of view. Excellent brightness!!
Pentax KX = 0.88x magnification, 93% field of view. Noticeably smaller view and not quite as bright as the MX.
Konica Autoreflex T4 = 0.89x magnification, 90% field of view. About the same brightness as the KX.
Pentax SP = 0.88x magnification, field-of-view not specified. The view through my 50mm Super-Takumar f1.4 lens is noticeably yellowish. I wonder how much the yellowed lens is affecting the brightness?
Konica Autoreflex T3n = 0.78x magnification, 92% field of view. Smaller view, and not quite as bright as the T4. For me, the viewfinder on this camera is marginal. Anything less in either magnification or brightness would prevent me from enjoying the camera in use.

GRHazelton · Oct 26, 2023

The Pentax Spotmatic F features full aperture metering with some Takumar lenses; it has provision for stopdown metering with any 42mm thread lens, which are abundant.
I have a Spotmatic F, and the standard trio of full aperture capable Takumars - 28mm, 50mm, and 135mm. The camera is a delight to use, fit and finish are exemplary, and everything operates smoothly. To my eye the VF is adequately bright, not as bright as my Pentax MX or Pentax LX, but good.
Here is an excellent overview of the Spotmatic F: https://www.35mmc.com/14/09/2020/pentax-spotmatic-f-review/
BTW, I seem to recall that Fujica made a 42mm full aperture metering SLR.

BobD · Oct 26, 2023

The Fujica ST801 has a large and bright viewfinder. It has a variation of the M42 lens mount. It can accept regular M42 lenses and, with lenses designed for that mount, can also provide open-aperture metering. It also uses a modern battery (PX28).

Fuji made lenses for it and I know that Tamron adapters were made for it as well as Vivitar TX adapters.

Bill Burk · Oct 26, 2023

Spotmatic F is awesome, though I am no fan of auto-off which occurs at low light levels. The one I have will center the needle when off. I always try to set f/stop and shutter to best guess before bringing the camera to my eye.

So I don’t know if it’s off or I guessed right when the needle is null. A traditional Spotmatic is always good when null.

ic-racer · Oct 26, 2023

Yes, the ST801.

reddesert · Oct 27, 2023

Open-aperture metering on an M42 body requires an extension to the mount standard with an extra pin or coupling. A few different manufacturers each came up with their own extension to the standard. To get open aperture metering you need to have the matching body and lenses of the type. (For example, for Mamiya it's SX, and you need the SX body and SX lens. You can put a non-SX body or lens on, but then you are back to stop-down metering.)

Is there something wrong with your Spotmatic that requires servicing? I would just enjoy it for what it is. Clean off the lens, the eyepiece, blow any dust off the mirror and focusing screen. If the lens has yellowed you may need to expose it to a UV lamp or the sun to clear it.

Paul Howell · Oct 27, 2023

Chinon ME3, open aperture using single pin M42 lens, it is aperture preferred auto exposure. As the user plunges the shutter release down the camera calculates the exposure and set the shutter speed. The viewfinder is about what I think is average brightness, 95% magnification, meter uses 2 Silicone Blue cells, sliver oxide batteries. Option for a (slow) motor winder.

runswithsizzers · Oct 27, 2023

reddesert said:
Open-aperture metering on an M42 body requires an extension to the mount standard with an extra pin or coupling. A few different manufacturers each came up with their own extension to the standard. To get open aperture metering you need to have the matching body and lenses of the type. (For example, for Mamiya it's SX, and you need the SX body and SX lens. You can put a non-SX body or lens on, but then you are back to stop-down metering.)

Is there something wrong with your Spotmatic that requires servicing? I would just enjoy it for what it is. Clean off the lens, the eyepiece, blow any dust off the mirror and focusing screen. If the lens has yellowed you may need to expose it to a UV lamp or the sun to clear it.

The function of the Spotmatic SP is unknown at this time. While dry-firing the shutter and watching the aperture, I do not see any obvious problems, but after 40-50 years wouldn't any foam light seals or mirror bumpers need to be replaced(?) As soon as I get a battery I can test the meter -- then I will shoot a test roll to see what (if anything) needs to be done. And to see how we get along.

I am still researching what UV light source I want to use to try to clear the lens. If clearing up the yellowed lens brightens up the viewfinder enough to really notice, then the Spotmatic might end up being a keeper. It looks and feels like a nicely made camera, and I want to love it. But my memories of using a Spotmatic back in the 1970s are telling me to keep looking.

tom43 · Oct 29, 2023

Without a doubt the M42 camera with the brightest viewfinder is the Bessaflex TM. It is a camera from the 2000s, so new batteries can be used.

runswithsizzers · Oct 29, 2023

BobD said:
The Fujica ST801 has a large and bright viewfinder. It has a variation of the M42 lens mount. It can accept regular M42 lenses and, with lenses designed for that mount, can also provide open-aperture metering. It also uses a modern battery (PX28).

Fuji made lenses for it and I know that Tamron adapters were made for it as well as Vivitar TX adapters.

ic-racer said:
Yes, the ST801.

Thank you both. I have never handled one, but the specifications for the Fujica ST801 look very attractive on paper.

runswithsizzers · Oct 29, 2023

tom43 said:
Without a doubt the M42 camera with the brightest viewfinder is the Bessaflex TM. It is a camera from the 2000s, so new batteries can be used.

The Bessaflex TM looks fantastic! For some reason, it was not on my radar. I had heard the name and seen a few photos, but just assumed it it was just another SLR from the 1960s-1970s. I am amazed to learn it was made so recently and to such high standards. But I would have to think twice before paying the current price for a camera with stop-down metering.

I think I need to run a roll through the Spotmatic SP to see how well I can get along with stop-down metering today, compared to how I remember it from the 1970s.

Thanks for the suggestion - it was fun to read about this amazing camera!

tom43 · Oct 30, 2023

Yes, the price is quite high, which is related to the lower production numbers. But overall it is a nice camera. It does not have the tank like build quality of the Spotties, but I like the lower weight, the bright viewfinder and the LEDs instead of a needle for checking exposure (very similar to the Praktica MTL50). Minor negative aspect: Unfortunately they have copied the metering lever and position from the Spotties, not from Praktica MTLs, which have better ergonomics.

jamesaz · Oct 30, 2023

Maybe 6-7 years ago I found an ST 801 with a 43-75 fujinon-z lens. It is so much fun it’s become my walking around camera. Not the sharpest lens I have ever used but the combination is really versatile. When using other M42 lenses metering is not as seamless but still workable.

toadhall · Oct 31, 2023

runswithsizzers said:
The function of the Spotmatic SP is unknown at this time. While dry-firing the shutter and watching the aperture, I do not see any obvious problems, but after 40-50 years wouldn't any foam light seals or mirror bumpers need to be replaced(?) As soon as I get a battery I can test the meter -- then I will shoot a test roll to see what (if anything) needs to be done. And to see how we get along.

I am still researching what UV light source I want to use to try to clear the lens. If clearing up the yellowed lens brightens up the viewfinder enough to really notice, then the Spotmatic might end up being a keeper. It looks and feels like a nicely made camera, and I want to love it. But my memories of using a Spotmatic back in the 1970s are telling me to keep looking.

I cleared my 50mm f1.4 by putting it on a south-facing window sill, tilted upwards, without a filter, and with aluminum foil - shiney side to lens - wrapped over the rear element. I can't recall how long I left it there, but the yellow was gone. But, I live in an area with a great deal of sunlight, and if I recall correctly, it was summer. So, YMMV.

runswithsizzers · Oct 31, 2023

toadhall said:
I cleared my 50mm f1.4 by putting it on a south-facing window sill, tilted upwards, without a filter, and with aluminum foil - shiney side to lens - wrapped over the rear element. I can't recall how long I left it there, but the yellow was gone. But, I live in an area with a great deal of sunlight, and if I recall correctly, it was summer. So, YMMV.

Thank you. I like the idea of using free sunlight, but I don't have the perfect place to leave the lens which is out of the weather but exposed to direct sunlight. My very limited research has been somewhat contraditory about how much UV light is blocked by window pane glass.

I have some nice south facing windows, and quite a bit of sun, but... My windows are double pane glass and they have an "low-e coating" to reduce solar gain. According to the window manufacturer, the coating "blocks 95% of the sun's damaging ultraviolet rays." Which makes me think I might be better off to try a UV lamp. So far, I have not verified which part of the UV spectrum is going to be the most effective for clearing the yellowed lens -- and therefore what kind of a UV source lamp I need.

runswithsizzers · Nov 5, 2023

Bottom line: the Spotmatic SP has issues, so I need to decide whether to send it off to Eric Hendrickson or to put it on a shelf and spend the money on either:
a. A more recent screw-mount Pentax with a brighter viewfinder and open-aperture metering, or,
b. Some other brand like the Fujica ST801.

If I understand correctly, the only Pentax screw-mount bodies that provide open-aperture metering are:
Spotmatic F
Electro Spotmatic
ES
ESII

Can anyone tell me if the viewfinder on any of those four Pentax cameras is noticeably brighter than a Spotmatic SP viewfinder?

Next, I will need to figure out how to tell which Pentax lenses support open-aperture metering. I know what to look for on the back of the lens, but is there any way to be sure which lenses support open aperture metering by the name on the lens or by looking at the front of the lens? For example, when I look at the list of M42-Screwmount-Normal-Primes on the Pentax Forum, how do I know which of those lenses can meter wide open?

tl;dr
Finally got a battery for the Spotmatic SP meter -- and it is not working as expected. With the lens lever set to Auto, and the switch next to the lens in the up position, the lens stops down, but rotating the aperture / shutter dial does not cause the meter needle to move up or down as expected. The needle does twitch sometimes, as if there might be a partial connection. When I do the battery check procedure as described in the Spotmatic Owner's Manual, the needle rapicly goes UP, not down as expected.

Also, I noticed my shutter speed dial rotates past 1000 to B (and vice versa). The shutter dials on my K-mount Pentax cameras have hard stops past 1000 and B, so I assume the Spotmatic SP is broken?

Flighter · Nov 5, 2023

runswithsizzers said:
Also, I noticed my shutter speed dial rotates past 1000 to B (and vice versa).

I think that's normal, both my SP1000s do that and which I understand are basically SPs without the self-timer.

darinwc · Nov 15, 2023

Honestly, if you want a bright screen, open-aperture metering, then just stick with what you have.
If you really wan the m42 experience, give up on one of those goals.

* A Spotmatic-f or ESii will give you the open-aperture metering. Screen is not as bright as your Pentax LX.

* Or, you can get an adapter for your LX so you can use the m42 screwmount lenses. You will have to stop them down to working aperture to meter and shoot.

runswithsizzers · Nov 15, 2023

darinwc said:
Honestly, if you want a bright screen, open-aperture metering, then just stick with what you have.
If you really wan the m42 experience, give up on one of those goals.

* A Spotmatic-f or ESii will give you the open-aperture metering. Screen is not as bright as your Pentax LX.

* Or, you can get an adapter for your LX so you can use the m42 screwmount lenses. You will have to stop them down to working aperture to meter and shoot.

I wish I had a Pentax LX, but what I actually have are a Pentax MX and a KX. But I have decided you are right, and I should just use my K-mount cameras and forget about screw mount.

The old Spotmatic SP just feels and looks like a nice solid camera, it makes me want to have it serviced -- but I know I will never use it as long as I have a working MX. I'm sure I'll be better off to spend the money on film, instead.

albireo · Nov 17, 2023

Can I quickly jump in and ask the m42 experts what's a good choice for a normal screw mount prime? Does not need to be super bright, anything f/1.7-f/2.8 max aperture would do.

Eg any pancakes in the 40/45/50mm range with good IQ?

runswithsizzers · Nov 17, 2023

albireo said:
Can I quickly jump in and ask the m42 experts what's a good choice for a normal screw mount prime? Does not need to be super bright, anything f/1.7-f/2.8 max aperture would do.

Eg any pancakes in the 40/45/50mm range with good IQ?

There are a lot of them. http://camera-wiki.org/wiki/42mm_screw_lenses

One thing to consider is, the quality of the lens coatings improved over time. For example, between 1964 and 1975 Pentax made four versions of the 50mm f1.4 screw mount lens. The first two versions were called "Super-Takumar" -- they were coated, but only the later two were labled "Super-Multi-Coated" or "SMC." Whether the improved coatings are worth seeking out may depend on whether or not you often find yourself shooting under contre-jour lighting conditions. https://petapixel.com/science-of-lens-coatings/

albireo · Nov 17, 2023

runswithsizzers said:
There are a lot of them. http://camera-wiki.org/wiki/42mm_screw_lenses

One thing to consider is, the quality of the lens coatings improved over time. For example, between 1964 and 1975 Pentax made four versions of the 50mm f1.4 screw mount lens. The first two versions were called "Super-Takumar" -- they were coated, but only the later two were labled "Super-Multi-Coated" or "SMC." Whether the improved coatings are worth seeking out may depend on whether or not you often find yourself shooting under contre-jour lighting conditions. https://petapixel.com/science-of-lens-coatings/

Thank you!

Kodachromeguy · Nov 17, 2023

albireo said:
Can I quickly jump in and ask the m42 experts what's a good choice for a normal screw mount prime? Does not need to be super bright, anything f/1.7-f/2.8 max aperture would do.

Among Pentax M42 lenses, almost everyone agrees that the 50mm f/1.4 and the 55mm f/1.8 lenses are remarkably good optically and mechanically. And they tend to age gracefully, with less trouble with haze than, in comparison, 1970s Leitz lenses.

In the 55s, the glass changed over time. My 1971 55 has a thorium element, while a later SMC version never yellowed. I cleared the yellow with the little table lamp from Ikea.

The earlier 50 1.4 had 8 elements, while the later models used 7 elements. The 8 has a fan base, but I have not seen evidence that it is superior optically.

The 50mm f/4 Macro-Takumar is also reputed to be excellent at all distances. Some diagrams show that it is a 4-element Tessar design.

MarkS · Nov 19, 2023

It occurs to me that m42-mount camera designs are all pre-1975, while the move toward bigger, brighter viewfinders in 35mm SLRs had hardly begun (I suppose with Olympus) by that time. Certainly the K-mount Pentax ME has a great viewfinder, and I'm sure that there are others.

GregY · Nov 19, 2023

MarkS said:
It occurs to me that m42-mount camera designs are all pre-1975, while the move toward bigger, brighter viewfinders in 35mm SLRs had hardly begun (I suppose with Olympus) by that time. Certainly the K-mount Pentax ME has a great viewfinder, and I'm sure that there are others.

Perhaps not necessarily brighter, but bigger? the Nikon F had a 100% viewfinder from the get-go, which made me happy to trade in my Nikkormat....

Which 35mm SLR screw mount camera (M42) has the biggest, brightest viewfinder and open aperture metering?

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