Light meters with reflective, incident and spot metering

[ic-racer]

Beyond technical considerations, what I have just learned is that with my particular phone model I can get perfectly accurate incident meterings, I've checked it well.

It is nice to see you got that to work. A while back I downloaded one of those apps and, either my iPhone was no good as a meter or it was poor software, but it was very slow to respond and never seemed to give the same readings of the same area twice. Due to the uncertainty, it was a pain to use. Maybe the software was intended for people with plastic cameras without meters.

 

[138S]

It is nice to see you got that to work. A while back I downloaded one of those apps and, either my iPhone was no good as a meter or it was poor software, but it was very slow to respond and never seemed to give the same readings of the same area twice. Due to the uncertainty, it was a pain to use. Maybe the software was intended for people with plastic cameras without meters.

My view is that it's not the app, but the nature of the light sensor in the phone, no App worked well in my later phone and all work well in my new one.

IMO the question is if the sensor has a diffuser on it or not.

We have to consider that the embedded lux meter is incorporated to allow auto-brightness feature for the screen, probably depending on the scrren quality (price) a more or less directional or diffuse sensor would be better. An iPhone has a very good screen with probably better anti-reflective and angle of view features, if they place a directional sensor this is because it provides the better evaluation to auto-adjust screen's bright, if they wanted to place a diffuser on the light sensor photocell this would had been cheap.

At the end my cheap phone sure has for sure that diffusion layer on the photocell, probably to have a more consistent auto-bright for that cheaper screen, but this makes it quite suitable for incident metering.

 

[Bill Burk]

Most of those cited only seem to have largely only referred to a meter if using colour. HCB was notorious for not caring for meters & for liking quite generously exposed negs (which irritated at least one of his printers - if it was Tri-X in certain developers, I can see why). And Atget wasn't really dealing with what we'd call a 'narrow latitude' system. The EV system is pretty accurate.

I think macfred meant that his favorite photographers didn’t care a lick for their light meters if they used it at all.

Too late for me, I like Minor White and Ansel Adams

 

[Bill Burk]

And really, I think it would be good to write more about Minor White and the mystique he lends to metering. He uses the word interface a lot to describe what goes on in the photographer’s mind between subject and print. And without the interface you are taking snapshots. (He allows for genius in that regard like Winogrand).

 

[radiant]

In the Owens Valley shot the camera is in the shadow so you are to measure the incident light in the shadow, while the far snowy mountain is illuminated by direct sun rays, having a very strong incident illumination around 3 stops higher.

I think you answered to your question; measure incident at the shadow, expose -3 stops ?

 

[grat]

What you quoted was a response to 138S talking about "incident" metering apps that use the front camera, stating they'd work more or less the same (perhaps more "directional" as a diffused actual incident meter. If that was the case, then any camera that meters off the sensor would read the same exposure whether pointed toward the light source or toward the subject, as it's designed to. That's obvious humbug.
As to others getting hung up on dome vs. disk diffuser, I think that's beside the point. The phone camera has no diffuser at all and as such direct light will strike the sensor, making the reading too high in these situations. So as far as these apps do work in such situations, it must be by computational power (identifying a light source in the picture to adjust the reading), I think error prone.

The problem is, you're equating a single, flat, unlensed CDS cell (which is what my incident meter has under that dome), with an array of photocells which are under a relatively small lens. The whole point of the dome is to gather light from various angles-- which is also what a lens does.

Laying both my smartphone and my incident meter on a table next to each other, and taking a reading, I actually get readings within .2 EV of each other. Explain.

 

[grat]

Is there anyone out here who practices photography ?

Well, obviously not, since no photographer can be interested in technical discussions *and* take photographs. Right?

 

[radiant]

A while back I downloaded one of those apps and, either my iPhone was no good as a meter or it was poor software, but it was very slow to respond and never seemed to give the same readings of the same area twice.

Try Lumu app (you don't need the sensor). It has a "spot" metering mode too! https://apps.apple.com/us/app/lumu-light-meter/id730969737

 

[138S]

I think you answered to your question; measure incident at the shadow, expose -3 stops ?

Sunny 16 says 4 stops from sunny to open shadow...



Still those are approximations. We all know that negative film has an ample latitude and it is possible to make take a good shot without metering, AA made his most famous image (Moonrise) with no meter...

But Adams also used the spot meter intensively, John Sexton also uses it:

Photography is an ample platform allowing room for unlimited ways to craft images...

We have to admire how Sexton controls his workflow, but also how Sally Man sometimes refuses to use a meter.

Still, to learn, there is nothing like having accurately metered the scene and taking notes. Later, when judging the result, we know how each spot resulted from its particular over/under exposure, providing totally precise feedback. From that feedback next time, after slecting the exposure, we can check with the spot meter how each spot will be over/under exposed, so we may make a good prediction.

In LF often we want to make accurate predictions, because an LF shot usually commands a way larger effort and cost. But of course this is not the general rule.

My view is that this is not about determining what is the best way to meter. IMO a LF photographer should master all the possible ways to meter, from smelling the scene to accurate spot metering, including of course Sunny 16. Later one does what he wants, but he does it after treasuring a solid criterion.

 

[BrianShaw]

My view is that this is not about determining what is the best way to meter. IMO a LF photographer should master all the possible ways to meter, from smelling the scene to accurate spot metering, including of course Sunny 16. Later one does what he wants, but he does it after treasuring a solid criterion.

Amen. Applies to all formats too.

It is part of learning one’s craft.

 

[Lachlan Young]

If you don't know how much Adams sometimes liked to burn the tonal values in the foreground into the floor, consider this earlier print. It looks like the light was much the same where Adams was standing as deeper into the scene. Certainly enough for him to have been able to check scene values with his reflected light Weston meter if he wanted.

Vedostuu's '-3 stops' comment was about how you index a shadow reading from a spot meter (for example) to give a correct meter reading to base your exposure off. Let's say your darkest shadows that you want a hint of detail in meter at an EV of 9 - if you index them to Zone II, you'll actually be basing your exposure off an EV of 12. Or you can use the IRE shadow index (-2 2/3 stops) etc. An incident meter used to read from your own shadow (using the correct EI compensation) should end up at essentially the same EV.

 

[Sirius Glass]

TEST PERFORMED

For incident metering, I've completed an extensive practical test, playing for some 60min in different illumination situations including direct sunlight, and pointing the meters to different directions.

Compared a Lux Meter to that App+Xiaomi Note 8 Pro.

Result: I got discrepances of about 15% nominal in the reading, this would be under 1/4 of stop perhaps 1/6. We may find that discrepance is common between commercial meters.

Disclaimer: Apps may allow to adjust corrections for the offset and gain, still some smartphones may sport a very directional senstivity that require a very different interpretation. IMO it can be recommended that anyone wanting to use the smartphone for incident metering he should check the consistence of the readings with an Lux meter or at least comparing with the spot metering on a grey card, checking different orientations to the light source.

(Since my Weston Master IV died I had no incident meter, personally I use Spot a lot, but I wanted to know if my particular phone could deliver a reliable reading if wanted, if I was always incident metering I would like a Sekonic or a charming Weston).

When calibrated they will all be the same.

 

[Sirius Glass]

Is there anyone out here who practices photography ?

With COVID we are all sitting around the house banging out gums but on the internet instead of in person.

 

[Sirius Glass]

I really have no idea why people want to make metering as difficult as possible - they should be able to get a more than sufficiently accurate exposure with one meter reading, two if they really need to know the contrast range.

They have nothing better to do with their lives. They also like endless mindless testing. No need to do photography when you can make taking a light reading of one scene last a life time.

 

[138S]

When calibrated they will all be the same.

Remove the dome of an incident meter and you'll realize why this is not only about calibration, and why the diffuser dome was placed on the photocell.

They have nothing better to do with their lives. They also like endless mindless testing. No need to do photography when you can make taking a light reading of one scene last a life time.

You can meter like you want, but you should realize why others meter accurately in some situations.

 

[Lachlan Young]

They have nothing better to do with their lives. They also like endless mindless testing. No need to do photography when you can make taking a light reading of one scene last a life time.

Indeed. And as the film of Adams shows, he sweeps the scene looking for the deepest shadow & brightest highlight he wants, allows for system flare (which also plays a role in determining his processing), indexes the shadow value to keep the deep shadows really dark & makes the exposure. And the process was vastly elongated/ repeated for the benefit of the film crew. All the SEI meter did was speed things up & essentially confirm what EV tables say.

It's about as diametrically opposed to the pointless 'practicing' the mindless testers engage in as it's possible to get. Without the crew (and without the Zone baggage), you could probably get the exposure with a single reading in seconds.

 

[138S]

They have nothing better to do with their lives. They also like endless mindless testing. No need to do photography when you can make taking a light reading of one scene last a life time.

For example in the shot bellow, personally I would spend some 8 seconds Spot Metering if shooting 35mm film, just I would check the resulting over/under exposure in the shop, the sign over it, the cars and the road.

If it as CDU II 8x10" LF slide film (of which I only have 43 sheets) then I would spend perhaps 1 minute thinking, if it was 8x10" HP5 I would spend around 30 seconds.

Now imagine yourself having to meter that scene for (say) a 8x10" Provia sheet with an incident meter. You have to go inside the shop to get the reading there, later walk to the car, then guess the incident power in the sign... and you are lucky because your differently illuminated subjects are not miles far.

In complex scenes Spot Metering is what allows you to have a very fast and accurate prediction of the result !!!!

In the situation bellow, just imagine you take a single incident reading in the camera place, LOL... you would have a high probability to trash a Provia 8x10" sheet, something painful one remembers for years.



https://www.nickcarverphotography.com/art/prints/

 

[Alan Edward Klein]

I was out yesterday and shot three 4x5's around sunset and after using my Minolta E-PL1 digital camera to set up the shots including exposure settings. I use the digital camera's screen and histogram to figure out the settings. Shot both Provia 100 and Ektachrome 100, both color chromes. I'm still fine-tuning the digital camera exposure meter process. So we'll see if I'm chasing windmills with this procedure.

 

[138S]

So we'll see if I'm chasing windmills with this procedure.

IMO this is pretty viable. Digital and slides have in common their limited highlight latitude, IMO the DSLR may provide a very acceptable preview on the resulting slide. Personally I would adjust that procedure with 35mm film. For well selected sample scenes I would use the same base exposure, then I would bracket both the 35mm film and the digital shots. This would tell what exposure compensation to use in the digital camera to take the preview shot in the way highlights would result similarly blown when overexposed. Perhaps to preview the shadows another exposure compensation has be used.

Also it would be important to disable some features in the DSLR.

Im my case, I tried to use the DSLR to preview/learn the color filtration effect, on a doubt (orange vs red) I have placed each filter in the DSLR and shot BW mode. What had been really useful to me was using 35mm to bracket filter type vs exposure just to learn, but sometimes y used the DSLR for the filter effect preview before spending a big sheet.

Still, for slides, what resulted the most useful to me was bracketing+spotmetering+taking_notes in different situation, to know how sky/clouds/terrain/people results at different over/under exposure levels, so know I've a criterion to refine and balance the exposure, and to select a graded ND. Negative film is more forgiving if enough exposure is provided... But you know, slides have to be nailed... and is the slide is a sheet then better to check it twice !!! "Mesure twice and cut once" = "Meter twice and nail the exposure of the slide"

 

[Alan Edward Klein]

IMO this is pretty viable. Digital and slides have in common their limited highlight latitude, IMO the DSLR may provide a very acceptable preview on the resulting slide. Personally I would adjust that procedure with 35mm film. For well selected sample scenes I would use the same base exposure, then I would bracket both the 35mm film and the digital shots. This would tell what exposure compensation to use in the digital camera to take the preview shot in the way highlights would result similarly blown when overexposed. Perhaps to preview the shadows another exposure compensation has be used.

Also it would be important to disable some features in the DSLR.

Im my case, I tried to use the DSLR to preview/learn the color filtration effect, on a doubt (orange vs red) I have placed each filter in the DSLR and shot BW mode. What had been really useful to me was using 35mm to bracket filter type vs exposure just to learn, but sometimes y used the DSLR for the filter effect preview before spending a big sheet.

Still, for slides, what resulted the most useful to me was bracketing+spotmetering+taking_notes in different situation, to know how sky/clouds/terrain/people results at different over/under exposure levels, so know I've a criterion to refine and balance the exposure, and to select a graded ND. Negative film is more forgiving if enough exposure is provided... But you know, slides have to be nailed... and is the slide is a sheet then better to check it twice !!! "Mesure twice and cut once" = "Meter twice and nail the exposure of the slide"

If I'm shooting chromes, I'll err on the histogram to the dark side so I don't clip the whites. Likewise, if I'm shooting BW negative film, I'll err with the histogram to the right so I capture the shadows and don;t clip them. If the range is acceptable so it all fits without clipping on either end, I'll stick the histogram in the middle and use that expsorue.

Of course, what I have to be careful with, is that film has less latitude than my digital camera. So the histogram may show no clipping at either end but the film's latitude, being smaller, might be clipping. I'm taking digital captures of my shot in addition to the film shots. I have to go back now and compare what the actual film looks like compared to the histograms. That's next on my research.

 

[138S]

Of course, what I have to be careful with, is that film has less latitude than my digital camera.

Yes... IMO this is... you have to correlate the highlight clipping in the histogram with the one in the slide.

Probably a sound way would be exposing well in the DSLR and knowing what +/- exposure compensation you have to adjust in the Slide exposure yo have the same clipping you allow in the histogram. So it would be the counter I pointed before... Expose in the digital camera to have acceptable highlights, then use the same base exposure for the 35mm test slide film, then bracket. This will tell you the exposure compensation for the slide that is to deliver a similar highlight latitude for the slide than for the Digital Camera pre-shot.

For what I used DSLR pre-shots is for learning studio portraiture, rigging the DSLR to a SINAR Norma, mostly to preview the illumination effects. The Norma was firing the DSLR and the DSLR was controlling the Bowens strobes, to refine my understanding of the modeling illumination. I also found that it was quite useful to realize the resulting expression in the subject and to know if eyes were well open...

DSLR can be a powerful aid for LF, IMO at all to substitute the classic metering ways, just a nice additional resource.

 

[Alan Edward Klein]

Yes... IMO this is... you have to correlate the highlight clipping in the histogram with the one in the slide.

Probably a sound way would be exposing well in the DSLR and knowing what +/- exposure compensation you have to adjust in the Slide exposure yo have the same clipping you allow in the histogram. So it would be the counter I pointed before... Expose in the digital camera to have acceptable highlights, then use the same base exposure for the 35mm test slide film, then bracket. This will tell you the exposure compensation for the slide that is to deliver a similar highlight latitude for the slide than for the Digital Camera pre-shot.

For what I used DSLR pre-shots is for learning studio portraiture, rigging the DSLR to a SINAR Norma, mostly to preview the illumination effects. The Norma was firing the DSLR and the DSLR was controlling the Bowens strobes, to refine my understanding of the modeling illumination. I also found that it was quite useful to realize the resulting expression in the subject and to know if eyes were well open...

DSLR can be a powerful aid for LF, IMO at all to substitute the classic metering ways, just a nice additional resource.

Until I got a 4x5 this year, all my medium format film shots were figured using a Minolta exposure meter. What got me to try the digital camera was Alex Burke's use of it and the fact that the camera aided in locating what shot I wanted and where to set up the tripod and camera beforehand. It allows me to see which lens to use through its zoom lens. I can also switch the display to BW to check whether to use color or BW film. I can flip the video on and record the scene and my settings and comments to be transcribed when I get home. So I figured to try using it as a meter as well?

What I do with the histogram, is when I see I'm pushing clipping, I back the display off a little from the appropriate side, and use that setting. I also look at the display and use my judgment of what looks good. I'm guessing a little of course, estimating what I think is just enough because the film is different than digital. That's why I now have to go back and compare the results to what the histograms on the digital shots were to see how off I was. Problem is, I;ve made a lot of mistakes because of being new to LF photography. But hopefully, I have enough results that I'll be able to see what's happening and adjust my methods.

 

[Sirius Glass]

Remove the dome of an incident meter and you'll realize why this is not only about calibration, and why the diffuser dome was placed on the photocell.

I never disputed why the dome is needed for incident readings and I have pointed out that some situations are best handled using incident readings. My point is that all of ones light meters should be calibrated for accuracy and consistency.

 

[Mainecoonmaniac]

Are there light meters that that have reflective, incident and spot metering modes all in one device?

I know that for example the Sekonic L-858D has spot metering and incident metering but I think it doesn’t have this reflective metering mode like my Gossen Profisix has.

Spot meter is reflective reading but more precise.

 

[Alan Edward Klein]

Spot meter is reflective reading but more precise.

I know what you mean. But to clarify it for those who might not, spot meters andother meters all have the same "precision". The meter provides readings that are at the same accuracy. All spot meters do is narrow how much area they are reading to let's say 1-degree wide angle. That doesn't make them more precise. In fact, if you select the wrong 1 degree to read, you'll get a worse reading than if you used center metering or matrix metering.