Using an external meter by choice

[wiltw]

Is there an equivalent to Sunny 16 for indoor lighting, or were the films so slow at the time Sunny 16 was invented that you always had to use flash?

Sunny 16 was invented because the sun is a generally consistent intensity source of light...broken clouds or fully overcast are somwhat consistent and so the corrolaries to Sunny 16 were invented.
But indoor light is totally inconsistent in its intensity, so a rule of thumb is not possible. In shooting almost daily during high school, my eye became 'calibrated' to ASA 400, 1/60 f/2 intensity. Not sure I could still do that 50+ years later!

 

[wiltw]

Wiltw… I don’t disagree that 1 reading is better than 2 with some arithmetic, but how about the condition of a single flat diffuser reading pointed toward the camera? Thanks for your experimental data!

If all you had was a flat diffuser, then the test shots show the Dunn method is a very good way to arrive at 'the same' results (close enough!) to accepted techniques. In fact, looking at the 3 shots, the Dunn method resulted in less apparent flare, with a somewhat contrastier appearance for the Macbeth chart...one might say that is 'better'!

I just took a pair of readings under the same conditions as my test, and the flat disk read -0.9EV compared to hemisphere, so that would have resulted in a shot more prone to flare than hemisphere or Dunn method.

 

[BrianShaw]

Ahhh.

Just for giggles, I went outside and metered a scene with the sun over my left shoulder. With a L-558 hemisphere out got EV14; with a LunaPro SBC got 13.9. As expected. With the L-558 hemisphere retracted, did Dunn Duplex and got EV 14, with a difference of 3EV between the two readings. Dunn Duplex with hemisphere out read 14.7.

Now I’m incentivized to pull out Dunn and refresh my memory on his assumptions.

 

[DREW WILEY]

There are real handheld spot meters, .... and then there is everything else. That solved it once for all for me.

 

[wiltw]

Ahhh.

Just for giggles, I went outside and metered a scene with the sun over my left shoulder. With a L-558 hemisphere out got EV14; with a LunaPro SBC got 13.9. As expected. With the L-558 hemisphere retracted, did Dunn Duplex and got EV 14, with a difference of 3EV between the two readings. Dunn Duplex with hemisphere out read 14.7.

Now I’m incentivized to pull out Dunn and refresh my memory on his assumptions.

My guess is that hemisphere measures some of the tangential light that the flat disk does not read, while averaging 'flat facing sun' and 'flat away from sun' results in 'about the same' result as 'hemisphere away from sun'...spherical trig.

 

[AgX]

Putting one of those diffuser discs on a lens does not turn an in-camera reflective meter into an incident meter. It still measures the light reflected off the subject and not the light falling on the subject, unless of course you take your diffuser equipped camera over to where the subject is and aim it back to the spot from which you intend to take the picture.

Of course.
I explained it somewhere above. And I had it about a dome, not a disc.

 

[BrianShaw]

A quick glance at Dunn (it’s a bit verbose writing style so a bit more study might be in order) indicates that Duplex is recommended primarily for side and frontal lighting scenarios. Not so much for diffused lighting situations. And I think he assumes hemisphere diffuser. Yet for me it works best when limited to a flat diffuser.

 

[BrianShaw]

My guess is that hemisphere measures some of the tangential light that the flat disk does not read, while averaging 'flat facing sun' and 'flat away from sun' results in 'about the same' result as 'hemisphere away from sun'...spherical trig.

EXACTLY… I should send you the original patent and journal article on Weston Invercone. Lots of science and geometry was involved. Fascinating reading if one is interested.

 

[AgX]

But nonetheles that design was not taken over by competitors over time.


By the way, I do not see an patent by E. Weston on that inverted cone.

 

[drmoss_ca]

The Kodak Retina III manual, on page 36, is perfectly clear about the proper metering technique.

Topcon was a pro camera, so I’m sure that their documentation was correct… and their pro users knew or were trained how to incident meter.

View attachment 295373

Thank you. That clearly says the meter must point from the subject to the taking position. Which is exactly what we should expect.

 

[BrianShaw]

But nonetheles that design was not taken over by competitors over time.

Yes, the Weston patent was unique to Weston meters. What I don’t know is why Norwood’s patent doesn’t appear to have been tight enough to preclude everyone else from using hemisphere diffuser. I’m not sure that I ever researched that detail.

 

[Sirius Glass]

That's my approach too. My Canon F1-N, T90, EF and Minolta Dynax 7's all agree to within a half stop. Allowing for metering pattern differences I'm happy with the results.

I'm itching to get out again with my Mamiya RZ67 and Gossen Profisix, (Luna Pro SBC), with Gosen Profispot attachment. I know it's a bulky old school meter but I can't yet justify a high-end Sekonic meter. One of these days...

Assuming those meters are working correctly and calibrated, there is no reason to buy the Sekonic meter at this time.

 

[BrianShaw]

Yes, the Weston patent held. Don Norwood’s hemisphere diffuser was a way around it to achieve the same effect. What I don’t know is why Norwood’s patent doesn’t appear to have been tight enough to preclude everyone else from using hemisphere diffuser. I’m not sure that I ever researched that detail.

Dyslexia strikes again… I got that completely backward: Weston’s Invercone was a way to get around Don Norwood’s patent on the hemisphere diffuser. Sorry.

(I edited the error out of prior post but kept it in the quote for this post, for posterity)

 

[AgX]

Yes, the Weston patent was unique to Weston meters. What I don’t know is why Norwood’s patent doesn’t appear to have been tight enough to preclude everyone else from using hemisphere diffuser. I’m not sure that I ever researched that detail.

As said there is no such for E. Weston. If someone can hint a respective inverted cone patent, I would be grateful.

 

[BrianShaw]

As said there is no such for E. Weston. If someone can hint a respective inverted cone patent, I would be grateful.

LOL… yes, Invercone was patented… two or 3 times I seem to recall. Not necessarily under E. Weston’s name. I can’t recall the inventors name at the moment and not inspired enough to look for it. But I know I’ve seen it/them.

if you haven’t seen this, it’s interesting reading:

http://dougkerr.net/Pumpkin/articles/Weston_Master_meters.pdf

 

[Paul Howell]

I have both a Weston Master VI and Ranger 9, the Master VI uses the inversacone and the Ranger 9 a small hemispherical cap when used for incident mode. Last time I tested both, they were a 1/2 stop from one another, the Master VI matched my Gossen which is the meter I keep calibrated.

 

[Sirius Glass]

I have both a Weston Master VI and Ranger 9, the Master VI uses the inversacone and the Ranger 9 a small hemispherical cap when used for incident mode. Last time I tested both, they were a 1/2 stop from one another, the Master VI matched my Gossen which is the meter I keep calibrated.

Get them all calibrated by the same lab at the same time and they will agree.

 

[Paul Howell]

Too expensive, by the way, my very old GE, the model with the removeable hood, matches my Gossen spot on, with the hood off it seems to meter in very low light for a selenium meter I use it with my Arugus . I use

 

[DREW WILEY]

Sirius - recalibrated by which (now out of business) lab? George at Quality Light Metric was the best. But he retired too.

 

[Sirius Glass]

Sirius - recalibrated by which (now out of business) lab? George at Quality Light Metric was the best. But he retired too.

And I have been asking around the Hollywood Los Angeles area to find out who the photographic-television-movie industries are now using.

 

[DREW WILEY]

Let us know when you find out. My custom is to keep a mint Pentax digital spotmeter on hand in storage only for checking my other spotmeters. Don't use it for anything else. Don't even keep a battery in it unless I need to check the others. And of course, it's also a bit of old age insurance for when it gets impossible to find replacements for these. But I'm pretty sure most of them will long outlast me. Even my oldest one, now 45 yrs old, and having gone through utter hell in the mountains, still reads dead on, even though it's held together with electrical tape. Quality LIght Metric recalibrated it only twice that whole time.

 

[Zathras]

And I have been asking around the Hollywood Los Angeles area to find out who the photographic-television-movie industries are now using.

If you find somebody who is still doing this, can you please share that info with us? I have 2 meters that need to be calibrated.
Thanks...

 

[Bill Burk]

Putting one of those diffuser discs on a lens does not turn an in-camera reflective meter into an incident meter. It still measures the light reflected off the subject and not the light falling on the subject, unless of course you take your diffuser equipped camera…

That’s right. You take that camera to subject position - meter pointing towards where the camera was - then put the camera back where it was, take off the dome and shoot.

 

[tokam]

You have a great meter. Other than reducing bulk, what other functionality do you need/want?

I guess nothing really. I would have liked the scale for setting ISO speed to be a bit larger. The distance between markings on the scale is literally the size of the pointer that you allign the scale width. Easy to get 1/3 stop out or more if not careful. Otherwise its a very sensitive and responsive meter and the null metering technique of centering the needle is quick and easy in practice. I'll probably keep it until one of us dies.

Assuming those meters are working correctly and calibrated, there is no reason to buy the Sekonic meter at this time.

That's the big question these days. My favourite technician, ex Canon trained, retired a few years ago and he certainly didn't know this meter. It could be a daunting prospect to get this meter serviced / calibrated in Australia. Even on the forum here it looks like American users are struggling since Quality Light Metric closed down and your population / industry base are massive compared to ours. Just keeping my fingers crossed.

 

[Pieter12]

And I have been asking around the Hollywood Los Angeles area to find out who the photographic-television-movie industries are now using.

Most DPs seem to use Spectra meters. I think they're still in buisness and will calibrate theirs and other meters. But since they could be the only source now, they might be extremely busy.