Exposure Advise On Meter

[smoke665]

It's seemed that lately my incident meter and my camera haven't always been on the same page, causing me to correct post. Tonight did a rather unscientific quick threesome, one as per the meter, then +1/3, and +2/3. If I'm reading these right, it looks like they are off. Light was adjusted for f/8 in all the shots, only the aperture was changed between shots. No adjustments other then crop post.

#1 as per meter f/8 and the corresponding histogram



#2 at f/7.1 and the corresponding histogram


#3 at f/6.3 and corresponding histogram


After looking at these I'm not so sure that I couldn't squeeze another 1/3 stop out, making the two read a full stop apart. Am I missing something here, or is it possible my meter could be that far off. This is an older model L308 which unfortunately doesn't have calibration adjustment but has been fairly close in the past. The battery seems to have lasted a long time, could it be a weak battery??? Or, do I need to be looking for a new meter?

 

[tirediron]

Are you looking only at the histogram, or at the actual exposure? To me, the correct exposure appears to be somewhere in between #1 and #2. #3 is distinctly over-exposed. A lot of the 'far left' you're seeing in the histogram is a result of the dark background, black meter, and dark table-top. To me, a meter that's within or less than 1/3 stop from visually ideal is within spec.

 

[smoke665]

Are you looking only at the histogram, or at the actual exposure? To me, the correct exposure appears to be somewhere in between #1 and #2. #3 is distinctly over-exposed. A lot of the 'far left' you're seeing in the histogram is a result of the dark background, black meter, and dark table-top. To me, a meter that's within or less than 1/3 stop from visually ideal is within spec.

Both. Looking at the image, judging highlights, midtones, shadows, saturation, and overall brightness. Using the histogram to judge the amount data available. Can you explain why you see #3 as overexposed? Granted it's bumping the right, but whites are not blown? I appreciate another set of eyes and opinion on this.

 

[tirediron]

Agree that nothing is blown, and the degree of over-exposure isn't significant, but the highlights just seem a bit hotter than I would opt for. This may also be due to differences in our monitors.

 

[dxqcanada]

Stick a greycard there and use your camera's reflective metering off that ... then compare that to the incident meter reading.

 

[smoke665]

Stick a greycard there and use your camera's reflective metering off that ... then compare that to the incident meter reading.

Incident is measuring flash. Camera reflective won't read incident/flash.

 

[smoke665]

but the highlights just seem a bit hotter than I would opt for.

I realize that when you're tweaking that last little bit it's a judgement call. Thanks for checking, having another opinion helps.

 

[dxqcanada]

Ah, I missed the flash part ... thought it was ambient light.

 

[Derrel]

Although we can see the histogram we need to know how much exposure correction has been applied to the jpeg images via the curves. Based upon your test scene I think you could brighten or darken these images quite easily so the tone curve would be more important to consider than just the histogram data. When looking at a JPEG image we have to consider how the raw file looked with a fairly flat or linear tone curve. It is possible that your default import curve is affecting our interpretation of the jpeg images?

It is not that uncommon for a reflective light meter reading to be somewhat different from an incident Light reading. Because your camera cannot measure Flash with its built-in reflected light meter, it is quite difficult to compare.

You have to be aware to that Nikon's 3D color aware Matrix metering gives you an exposure reading that is close to perfect based upon not only the reflecting light value but also upon the color that the meter has determined an object is. The Nikon 3D color Matrix metering can differentiate between white sand,grey sand, and brown sand because it is a color-aware metering device, whereas a light meter is a dumb,color-blind device which is designed to give you a reading which has to be interpreted somewhat. The modern Nikon is metering for color positive, RGB digital...

 

[smoke665]

Although we can see the histogram we need to know how much exposure correction has been applied to the jpeg images via the curves. Based upon your test scene I think you could brighten or darken these images quite easily so the tone curve would be more important to consider than just the histogram data

Hey man, hoping you'd chime in. While the camera preview is always a guess as to what the "camera gods" in their infinite wisdom have applied, I was careful to make sure I had no presets applied including tone curves or camera profiles when I imported to Lr. Once there, the only adjustments made was to crop. I assumed that on export Adobe generated a JPEG that should have been devoid of any editing enhancements.

You've confused me on reflective readings. The canera was on manual. The incident meter was used to adjust the flash (speedlight) to f/8. No camera metering was used. The light and shutter remained constant in the three shots, only the aperature was changed manually.

My concern has been that I was originally opening up a 1/3 from the incident reading of the meter, but lately it seems that I've had to add increasingly more exposure compensation post. The test shots seem to indicate to me that the meter is in fact reading significantly under exposed.

 

[Derrel]

Every jpeg image has some type of tone curve applied to it.

If you need to add exposure then perhaps something in your system needs to be calibrated more exhaustively.

One thing I can think of might be how you have the meter sitting in relation to your strobes. For example are you pointing the meter at the camera, or directly at the front face of the light modifier? You might see if there is much difference. Perhaps you prefer a more open Shadow. Incident light metering in my opinion is great for getting the Highlight tone value set, but that does not determine how about your shadows and midtones look.

Most incident light meters will give you a good highlight tone when you are using a color positive system, such as color slide film, or modern digital.

I think you should be aware that there are two schools of thought as far as where the dome is pointed when metering. One school of thought holds that the hemisphere should be pointed straight ahead,at the camera, while the other school of thought sees the photographer aiming the hemisphere directly at the main light.

Secondarily let me say that your light meter uses what I call a "small hemisphere", whereas my Minolta uses a much larger and more gently rounded sphere. Perhaps this smaller hemisphere is more sensitive to aiming differences.

Your your original post seemed to indicate that you were having a difference of opinion between your camera meter and your light meter and that is what I was talking about

 

[Derrel]

Let me state it again:every jpeg image created from a raw file has had some type of tone curve applied. This is a very important part of how bright the image looks. Just open the image and go to the curves dialog and you will see exactly what the Adobe default curve is. This curve could greatly affect your interpretation of the exposure.

 

[Derrel]

It's seemed that lately my incident meter and my camera haven't always been on the same page...snip

I am not exactly sure what you mean by this, but this is unclear

 

[JBPhotog]

The best way to determine exposure accuracy is shoot a control target that has a full scale of known densities such as a colour checker, grey card with reference data or my preference Sekonic Exposure Profile Target II. That way you can check the RGB values in post to known values on the target. Back in the film days this was a common process followed up by diligent processing and final densitometry readings for both negative and reversal emulsions.

For digital it is a wee bit different as in shooting in a particular profile can influence readings but a known single grey value should give you very close exposure guidance. The caveats is, it should not be a WB card since it’s only purpose is to set WB rather than exposure, so use an exposure target for best results.

Also, if you flash exposures are suspect, likely the incident ambient readings are too. A sunny day, exposure target and filling the frame with your target with the lens at infinity should confirm both camera and handheld meter to the sunny 16 rule.

 

[smoke665]

It's seemed that lately my incident meter and my camera haven't always been on the same page...snip

I am not exactly sure what you mean by this, but this is unclear

Sorry I may be saying it wrong. In this example my incident meter is reading f/8 with the flash, but if I set my camera to f/8 the image is underexposed. Its an older Seconics meter that I've had for awhile, I've always had to open up about a third stop from what the meter reads, but of late it seems to be getting worse. I'm having to correct the exposure more and more in post.

As to any curve adjustment applied to the JPEG I'm not seeing it reflected when viewing in Lr?

Also, if you flash exposures are suspect, likely the incident ambient readings are too.

As I rarely, if ever, use the meter for reflective readings, relying instead on the camera metering, you could be right. I've been looking at exposure targets for some time now, but kept postponing the purchase. Might be time. I have an Expo Disc that was part of a box of stuff I bought, but never used. Supposedly it can be used to dial in an 18% gray exposure by centering the spike in the histogram of a test image.

Another thought I've had is how much could different lenses have in the equation?