Pentax Spot Meter V Modification - Unique model...

holmburgers · Apr 19, 2010

Hey there,

So I have in my possession a unique Pentax Spot Meter V. I purchased it with a package deal of Redlake Hycam stuff. The Hycam was a widely used 16mm high speed movie camera. It's capable of 10,000 FPS... Could make a bullet look like a snail!

But anyways, little did I know, the spot meter that came with it has been calibrated to use specifically with this camera. Luckily, it appears the only thing different is the "deepest" plate on the exposure calculator dial. It's easy enough to access and remove, so I need to determine a good way to modify this plate back to normal shutter speed values. Film speed, and aperture are unaffected and appear to be identical to other Pentax V's.

It's in excellent shape, and I picked it up for a song, so it's worth the effort to fix it. What would you do in this situation? What would be the best way to put meaningful values on this plate? Anyone got a broken Pentax V kicking around that I can take for parts?

Thanks all,

Chris 'holmburgers' H.

P.S. The plate in question says "calibrated for 1/2.5 shutter" (degree's or seconds??? I'm thinking degrees) and then it goes from 100 to 50k PPS, which again, is meaningless at the moment.

Chan Tran · Apr 19, 2010

How about using it as is? I wouldn't modify the meter because the Pentax Spotmeter V like many others the actual reading it gives you is the needle in the viewfinder. The dial is only a calculator. It would make it more fun to use.

holmburgers · Apr 19, 2010

Haha, I don't know about "more fun"! But I agree, the only modification I want to make is on the dial. I'm not gonna go inside and mess w/ anything electronic.

Basically, I can get to the dial and unscrew the plates. So I could easily replace it w/ a plate from a broken V or I could paint over it, put a sticker, decal or something like that. But, I'm not sure where exactly to put the values, and I want to be as accurate as possible. On the other hand, if someone can help me decode the meter, I could probably get by with a conversion table.

lxdude · Apr 19, 2010

Well, I just saw today that KEH has an inoperative Pentax 1/21 spotmeter in their "as is" section. Maybe that will have what you need?

holmburgers · Apr 19, 2010

Hmmm, not bad at all. But, for $29 I might try a DIY solution first.

If someone could tell me, at a specific film speed & meter # (not sure, are those EV numbers?) what the shutter speed is, then I could go about creating a table or something like that.

Chan Tran · Apr 19, 2010

The readout inside the viewfinder should be EV number for ISO100. So if you read a gray card under sunny 16 lighting condition it should read right around 14 and 2/3. If this is true then the meter has not been recalibrated electronically and you're good. Now if you can post a picture of the dial I think I can decipher it.

holmburgers · Apr 19, 2010

Ok, I'll see what I can do. I can't post it immediately, but I might PM you once I can get a picture.

Mike Wilde · Apr 19, 2010

Look up "Fred Parker - The Ultimate Exposure Calculator" on the web. One of the tables in the back will give you the information you need to redo the back plate.

unclemack · Apr 19, 2010

If the dial has been painted over then you may be able to remove the later paint and, if you're lucky, maybe the original scale could still be there?
I removed badly-brushed matt black paint from a motorcycle tank once & found absolutely pristine original finish underneath. People can be strange...

holmburgers · Apr 20, 2010

Mike, thank you, I'll check that out.

Unclemack, unfortunately it appears to be a manufactured plate, not just a paint-over. I think this company did modifications for their specific cameras, and they must've had their own back plates made up.

RalphLambrecht · Apr 20, 2010

Chan Tran said:
The readout inside the viewfinder should be EV number for ISO100. So if you read a gray card under sunny 16 lighting condition it should read right around 14 and 2/3. If this is true then the meter has not been recalibrated electronically and you're good. Now if you can post a picture of the dial I think I can decipher it.

Please note, EV numbers simply specify a shutter/aperture combination and are independent of film speed (see attachment).

However, the sunny-16 suggestion for ISO 125/22 is a good one, because EV-15 is the combination of f/16 at 1/125s, and that is the Zone-V exposure for a film of at that speed in bright sunlight.

holmburgers · Apr 20, 2010

If EV is what you say it is, then what do the 1-19 numbers mean in the Pentax V? Since it's uncoupled, are they just arbitrary values?

So, by using published data/common knowledge, how should I do the proper markings on the shutter speed plate? I guess, if you just told me what SS resulted from #4 on the value dial @ ISO 100, f/5.6 (for example), then I could do the rest just by using the law of reciprocity.

Q.G. · Apr 20, 2010

Aren't the "EV" numbers on Pentax spotmeters just numbers to transfer to the scale, which then tells you what to set, and not (or rather, only when the 'right' ISO is set) what real EV numbers are?

holmburgers · Apr 20, 2010

that's what I'm understanding it to be.

RalphLambrecht · Apr 20, 2010

Q.G. said:
Aren't the "EV" numbers on Pentax spotmeters just numbers to transfer to the scale, which then tells you what to set, and not (or rather, only when the 'right' ISO is set) what real EV numbers are?

exactly

RalphLambrecht · Apr 20, 2010

holmburgers said:
...I guess, if you just told me what SS resulted from #4 on the value dial @ ISO 100, f/5.6 (for example), then I could do the rest just by using the law of reciprocity.

On my meter the following lines up exactly:

ISO 100
Time 30
f/stop 32
EV 15

holmburgers · Apr 20, 2010

Awesome, thank you. Now I have to go about the task of writing very very small.

RalphLambrecht · Apr 20, 2010

holmburgers said:
Awesome, thank you. Now I have to go about the task of writing very very small.

While you're at it, consider this:

Dead Link Removed

find more here:

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holmburgers · Apr 20, 2010

very cool, i think I will print out this one.... Dead Link Removed

RalphLambrecht · Apr 20, 2010

holmburgers said:
very cool, i think I will print out this one.... Dead Link Removed

Yeah, that's the one. I was just checking if you're paying attention.

Chan Tran · Apr 20, 2010

the value as readout in the viewfinder is the EV number for ISO 100, (or some may call it LV). The calculating dial is needed to show the user which shutter speed and aperture can be used as well as for a different ISO film speed.

paul ewins · Apr 20, 2010

Chris, does the plate really look home made? Pentax made the spotmeters in two versions; the regular one that most of us use and one for movie cameras which is called the Spotmeter V-FL since it has a Foot-Lambert scale.

holmburgers · Apr 21, 2010

No, it doesn't look home made. It was manufactured by Redlake, makers of the Hycam II high-speed camera.

I looked at the manual, and it's not the foot-lambert one, it's definitely just a V, but with the shutter speed plate swapped out for this proprietary one.

Pentax Spot Meter V Modification - Unique model...

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