[CMG]

Do you understand the purpose of this setting? it sounds like perhaps you don't. It's not like you cam just make the setting then expect to see a different result in your pictures. It's mostly just a matter of giving *you* the photographer more control when you choose to apply exposure compensation or switch to M (manual) exposure mode.

So, it's like if you had a stereo with a volume control knob one of which had ten clicks between minimum and maximum volue and the other had 15 clicks, but the actual minimum and maximum were the same on both stereos. One just allows for finer control over the volume thanthe other. You wouldn't be able to tell the difference between the two steroes just by listening to them. It's just that one would give you finer control oer the volume than the other.

Back to cameras, 1/3 EV is like the knob with 15 clicks - it gives you finer control. But that's not always a good thing, if it means you have to think harder in order to take advantage of that control. Only you can make that decision. But you can't even start pn that process until you understand the purpose of the setting.

Great explanation! My question still is...how much finer is the finer control and is it more of a "bell and whistle" feature than something that makes a meaningful difference in exposure or does it unnecessarily complicate things. I shoot JPEG and I try to get my exposures correct (I try my best!), so one might propose that 1/3 stops might be helpful. Then again, it is my understanding that 1/3 stops are a relatively recent development in digital photography, whereas in the "old days" of modern film photography stops were only 1/2. Sometimes I wonder if 1/3 stops were created more the EV compensation in auto-modes and since it's built into the camera it can be used in manual mode as well but not really why it was developed. Thoughts??

[emalvick]

It only makes things complicated if you think too much about it.

If I was shooting JPG exclusively, I'd probably be using 1/3 stop intervals, but I know from past experiences that I would be taking so many photos trying to get it perfect that 1/3 wouldn't seem like enough. Currently, I shoot RAW, and 1/2 is enough. I'm confident that within 1/2 stop I can use PP to get me right on and I won't see any detrimental effects. I also appreciate 1/2 stop increments because it makes the mental math of adjusting exposure on the camera easier. With 1/3 of a stop, it's a bit harder to reason out exactly how you might adjust things and I felt I was more or less making educated guesses about how my adjustments intertwined with each other (A, Shutter Speed, and ISO). In hindsight, I'm guessing that even with JPG that if you can get pretty much right, the difference between using 1/2 to 1/3 is really going to be at most 1/6 of a stop off from using one or the other.

Question is how much does that 1/6th matter to you?

As for why 1/3 developed... My guess it was a bit of marketing. With digital, you could in theory program whatever you want in terms of increments and steps. It may not be practical, but never-the-less possible. 1/3 was probably a way to sound better than 1/2 stop while remaining practical as far as handling goes. I'm only guessing.

I also have noticed that in using 1/2 stop increments the software lets you go further when setting the maximum and minimum limits. Going back to Mark's example, it's as if the camera is saying you can have 12 increments of adjustment no matter the step you choose, so with 1/2 stop you get -3 to +3 while with the 1/3 stop you get -2 to +2.

[Just1MoreDave]

...Then again, it is my understanding that 1/3 stops are a relatively recent development in digital photography, whereas in the "old days" of modern film photography stops were only 1/2. Sometimes I wonder if 1/3 stops were created more the EV compensation in auto-modes and since it's built into the camera it can be used in manual mode as well but not really why it was developed. Thoughts??

On the shutter speed dial of even a higher-end all-mechanical film camera, like the Pentax MX, speeds are only in full stops. All-mechanical (i.e., M series or older) lenses don't always have half-stops either. With a lens, you can put the aperture ring in between and get an intermediate aperture, but I don't know about shutter speed.

As soon as shutter speeds could be controlled electronically, though, cameras started to use them. Pentax introduced that feature even before the K-mount. The shutter could have any speed so the ultimate exposure value was infinite, even if you were stuck with using film at its rated ISO and the click-stops on the aperture ring. With the KA mount, apertures could match the shutter speeds. At first these abilities were only in auto modes. It took a while before the cameras allowed you to set 1/3 stops directly like you can now, not just in auto modes.

I think partly the 1/3 stop feature was added because they could easily do it, and partly because it could be useful. The real question is, how well can your meter measure the scene? With either scale and an unsophisticated meter, you'll have to make constant adjustments to get perfect exposures.

edit: in one of my Photoshop books, there's an example where the author increases exposure in Adobe Camera RAW by 0.89 stops. I think he missed the discussion of significant digits in science.

[TomTextura]

I also have noticed that in using 1/2 stop increments the software lets you go further when setting the maximum and minimum limits. Going back to Mark's example, it's as if the camera is saying you can have 12 increments of adjustment no matter the step you choose, so with 1/2 stop you get -3 to +3 while with the 1/3 stop you get -2 to +2.

I think that's just pertaining to the EV display in the viewfinder or on your top LCD. You can still go beyond +/- 2 when using 1/3 stops but you won't see it displayed; there's just not room to show it.

[emalvick]

That's probably true... I don't really use the EV beyond +1 anyway. I have more confidence in using M mode at that point. I guess I hadn't really paid that close attention as I've found it a bit troubling when I get out to that point.

I think that is just a quirk in how I think of exposure compensation. I'm asking the camera to compensate from what it thinks is right towards what I think is right. My problem is that when the camera gets to a point where I think it is over 1 stop off, I don't have much faith in its estimate to begin with. I know it's silly, but I go to manual mode at that point and adjust per my own judgments, thus my earlier preference to 1/2 stop adjustments. It's a lot easier, especially with aperture, to mentally adjust exposure using 1/2 stop increments than 1/3. It keeps me from over-thinking.

[Paninic]

For me, the problem of this choice it's really like playing golf. Before I had a driver, a w3, a w5, a w7...and sorry even a w9...in my bag...At many golf shots, I was a really problem to know what club , 'll be the better...and then a for me, much time the reason of the bad shot...because I had not choosen the good...Damned!!!!....I don't tell you all my regrets then along the course...At least, I had an excuse...this always very important at the club-house, to explain your score to your friends....
Now I have only the driver, a wood 5 and I begin my set iron with my 5.....No more questions and It's fine and relax...

It's the reason I 've also set my Kx with 1/2 stop...less questions, more tranquillity...as when I had my old reflex 24x36...only one " click " between 2 values of the ring apertures ( 1/2 ) and it was fine and enough for 35 years....sorry for my " fenchy " english....

Conclusion...1/2 step if fine for me....I think we are never at the level of the fantastic technicity of the new materials...simplicity is the best!

[tibbitts]

My film cameras only had 1/3rd stop clicks, but I usually set the dial in-between (it usually didn't get bumped one way or the other.) So I use 1/2 on my Pentax digital cameras. With the digital histogram, as long as I've got both high and low values recorded, I'm good. I think my eyes would have trouble delineating that 1/6th stop in from either end, and realistically I might miss the occasional blinkie as well if I was just barely over or under, so I don't worry about that last fraction of a stop.

Paul