Metering and Histogram

[dogonwheels]

Hi. I hope this is not a stupid question. But im wondering...with digital photography and the instant access to view your photos. Is there any use in using a light meter ? or i guess im wondering why people use the different metering modes in their camera...

with access to the histogram you can see the results right away and make any adjustments.....

anyone feel like sharing their opinions?

[E.T]

Not really unless you want to retain old habit.

Different metering modes are for situations with too big dynamic range so that you can select what part you expose right.
That's where live exposure preview (image in LCD or EVF is literally what sensor sees ) helps... Actually there's no need for changing metering mode with good camera, just use exposure compensation. And if you want to capture widest dynamic range histogram is excellent help for that... or avoiding clipped highlights, also in high dynamic range situation it shows well how changing contrast setting affects to clipping of extremes. (decreasing contrast of incamera JPEGs helps somewhat in high dynamic range situation)

Now DLSRs are just halfly in digital age and lack live preview and histogram. (they have post-preview)

dslr:

[NHL]

I tend to agree with the 'live' histogram - It's the major advantage of EVF based camera over dSLR's (especially on manual)

From Steve's review on the A2:


Basically What You See Is What You Get in the manual mode when you adjust the aperture or shutter in the EVF on the final image (The Hasselblad has a live histogram too)!

No review required - It's all done before the shot...
-> One can still do an AE lock and still move the histogram around :idea:

I keep saying it, but I believe that a real time (holographic) histogram will be the next big thing in DSLR's. Real-time histograms will make light meters go the way of the dinosauers. I took this with an Minolta A200 in manual mode after fiddeling with it for about 10 minutes...

Here's the EXIF info:

2005:01:06 16:29:54
11.4mm
44mm (in 35mm film)
1/13 sec, f/4.5
Mode: Manual
Metering: Multi-segment
ISO: 50
White balance: Auto
Flash: On
File size: 116KB
Image size: 414 x 640
Saturation: Normal
Sharpness: Normal
Contrast: Normal


More histogram info here:

http://www.outbackphoto.com/workflow/wf_41/essay.html

[kassandro]

I certainly like histograms, but I don't like that each pixel receives the same weight in an histograms. Pixels near the margin simply should get less weight than those near the center. Thus their should be a broad choice for histogram weights. Unfortunately I haven't yet seen that even in image processing software.

[BillDrew]

kassandro wrote:

I certainly like histograms, but I don't like that each pixel receives the same weight in an histograms. Pixels near the margin simply should get less weight than those near the center. Thus their should be a broad choice for histogram weights. Unfortunately I haven't yet seen that even in image processing software.

That is one of the few good usesof digital zoom: get the histogram readingsusing digital zoom to set the exposure on the most critical part of the image, then cut off the digital zoom to take the shot. Obviously requires manual exposure-f/stop settings, but thatis normal if you are being that carefull/fussy about the shot. Something I miss on my KM5d - I'd guess none of the dSLRs have digital zoom.

[JimC]

kassandro wrote:

I certainly like histograms, but I don't like that each pixel receives the same weight in an histograms. Pixels near the margin simply should get less weight than those near the center. Thus their should be a broad choice for histogram weights. Unfortunately I haven't yet seen that even in image processing software.

It depends on what you're shooting, Your primary subject may be near the edge of the frame, depending on the subject and the composition you want.

Also, you can use center weighted metering so that more emphasis for metering purposes is placed on the center of the frame with most models, if the scene you are shooting requires more emphasis in the center.

You've also got things like blinking highlights and shadows with some models, so you can see how the exposure choice impacts elements throughout the frame when you hit dynamic range limits (showing both under and overexposed areas), and you can judge for yourself if the exposure selected is adequate by using a combination of available tools (how the exposure looks, blinking shadows and highlights, as well as the histogram itself).

I'm pretty sure that the Acme 3000 has the features you're looking for (not that it really needs them, because of it's huge dynamic range). BillDrew is our resident expert on that model (Steve has never even received the marketing specs for it, much less a model to test). So, perhaps BillDrew can fill in members on how it's histogram features work at some point. ;-)

P.S.

I did a quick forums search to see if the Acme 3000 histogram has been discussed before. But, it didn't find anything on that feature (although it's 20 stop dynamic range has been previously mentioned).

http://www.stevesforums.com/forums/s...mp;q=acme+3000

[BillDrew]

You canget information on the Acme 3000 from any of the Brooklyn mail order dealers hiding near the bottom of the seller rating lists. Just give them your credit card information, and they will tell you the camera will do whatever you it is you want it to do. (That only applies if your credit card has a high remaining balance.)