Shoot to the right? Backbutton focusing? Opinions?

[MTVision]

I've been reading a bunch of stuff on a few different forums and these 2 topics come up a lot and I was just wondering about the opinions of you TPF members.

In one forum I was lead to this link

http://www.luminous-landscape.com/tutorials/expose-right.shtml

There are 2 articles - one written in 2003 and one written in august of this year.

I had heard of shooting to the right before but never really understood it. I always tried to get my little meter to go one line to the right of center. I'm just now trying to check my histogram and NOT the jpeg. I know now that it's not an accurate representation of the exposure but hey -I've only had a DSLR since July!

The articles, in the link above, state that you should shoot to the right hand fifth of the histogram (just before clipping) because there are more tonal values (maybe?) there. If you aren't shooting that way you are basically wasting half of "the encoding levels of your camera."

Does everybody agree with this? Does everybody shoot to the right? Opinions? Is there where an external light meter could come in handy?

Also, what if you know the sky is going to blow out, even when your camera says its a correct exposure, do you still shoot to the right?

Now, the last part of my mini-novel - back button focusing.

I had never heard of this until just recently and I have actually been using it. On another forum, in a thread about nailing focus, a large number of people recommended backbutton focusing. They said that using this method can be more accurate.

I haven't actually noticed a difference in my focusing skills since I've been using it but then again I haven't been doing either very long.

Once again who uses this method? Who doesn't? And what are your opinions on it.

Sorry for the mini-novel! Thanks in advance!

 

[Kerbouchard]

I do both, sometimes.

It just depends. Most people refer to it as ETTR(expose to the right) so you might have a better time searching for that term. In any case, you make sure nothing important is clipping, but then again, your histogram is also based on the jpeg thumbnail that is generated(even when you are shooting RAW), so your histogram isn't exactly correct. It's more important when you are at high ISO to reduce noise and extend dynamic range. In typical situations, there just isn't that much of a difference.

As far as AF-on, I prefer it. I feel it gives me more options. I can basically have my camera set up on AF-C, but I can make it act like AF-C or AF-S depending on which one is more appropriate for the shot. Easier than switching modes.

 

[MTVision]

I do both, sometimes.

It just depends. Most people refer to it as ETTR(expose to the right) so you might have a better time searching for that term. In any case, you make sure nothing important is clipping, but then again, your histogram is also based on the jpeg thumbnail that is generated(even when you are shooting RAW), so your histogram isn't exactly correct. It's more important when you are at high ISO to reduce noise and extend dynamic range. In typical situations, there just isn't that much of a difference.

As far as AF-on, I prefer it. I feel it gives me more options. I can basically have my camera set up on AF-C, but I can make it act like AF-C or AF-S depending on which one is more appropriate for the shot. Easier than switching modes.

Thanks! I was hoping you would post! In that article I read it did mention that about the histogram being based on the jpeg. Another question - can you tell if your RAW image is properly exposes by looking at the jpeg? Is it a skill I can gain by experience or is it just always guesswork?

Sorry - they are probably dumb questions!

 

[Kerbouchard]

I do both, sometimes.

It just depends. Most people refer to it as ETTR(expose to the right) so you might have a better time searching for that term. In any case, you make sure nothing important is clipping, but then again, your histogram is also based on the jpeg thumbnail that is generated(even when you are shooting RAW), so your histogram isn't exactly correct. It's more important when you are at high ISO to reduce noise and extend dynamic range. In typical situations, there just isn't that much of a difference.

As far as AF-on, I prefer it. I feel it gives me more options. I can basically have my camera set up on AF-C, but I can make it act like AF-C or AF-S depending on which one is more appropriate for the shot. Easier than switching modes.

Thanks! I was hoping you would post! In that article I read it did mention that about the histogram being based on the jpeg. Another question - can you tell if your RAW image is properly exposes by looking at the jpeg? Is it a skill I can gain by experience or is it just always guesswork?

Sorry - they are probably dumb questions!

It depends on how far you want to take it and how accurate you want to be. They make something called a unibal. It lets you set a custom white balance that will give you an accurate histogram(the problem is, all your files look green until you correct the white balance later). As far as having a fairly accurate histogram without going that far, you can do most of it in your picture settings. Obviously, increasing saturation, contrast, or brightness will impact the histogram. Also, things like active D lighting will effect it. A relatively standard picture control will get you pretty close.

Like you posted in your original post, this was a much bigger deal in 2003 when DSLR's couldn't shoot clean at ISO 400, much less ISO 1600.

There are two main principles behind it. One, most of your dynamic range is towards the brighter end. It's just the way the math works out. By keeping most of your data on the lower end, you are limiting your options. The other aspect is signal to noise ratio. We have all experienced it in many ways through our normal lives. For instance, when you are driving on some deserted highway, but you still want to listen to the radio. The signal gets weaker, so you turn the volume up, and the static gets stronger.

Same thing for a DSLR. There will always be noise in electrical circuitry(although with modern cameras, it has decreased significantly). The way that noise is masked is by having a strong signal, i.e. exposure. If you have lots of good data and only a little bad data, the bad data(noise) isn't so apparent. If your shot is underexposed, then there isn't that much good data, but there is still the same amount of bad data, so the noise is more apparent.

ETTR has a lot of valid points for critical shots. It does take more time in post processing, and it will generally not give you usable SOOC pictures, but it does have it's merits. I just don't know that it needs to go to the extremes that it did in 2003 for 99% of photographers. The Unibal never really caught on, and most people just assume the histogram is close enough(unless you have crazy picture controls set).

As far as judging exposure/histograms by looking at the JPEG preview on your LCD, that is difficult, and one that isn't really easy to get better at even with practice. The ambient light plays such a big role in how your LCD looks that it is sometimes impossible to judge proper exposure. The blinkies are an invaluable feature. Look at what is blinking. If it's important to your shot, reshoot it. If it's not, don't worry about it. Reading a histogram is also something that can be learned, but can be a bit misleading. If there is a light source or a highly reflective object in the scene, the histogram could show overexposure, but that might be okay depending on the subject matter.

Personally, I use the blinkies for about 90% of shots. For the 10% I really care about, I will use a calibration target and put the whites, greys, and blacks exactly where I want them. FWIW, I use this one, although if I was buying it again, I would probably get the larger one... http://www.adorama.com/PVOS6.html

Perfect white balance and perfect exposure...everytime. I use it to take a custom white balance, and then I just take a regular shot of the target, look at the histogram, and I can see exactly where the black spike is, where the grey spike is, and where the white spike is. I'll adjust the exposure if I need to, and I'm good to go with a perfect white balance and a perfect exposure(or at least a technically perfect wb and exposure)...I suppose creative license could take the shot somewhere else, but I figure perfect is a pretty good place to start from.

 

[Village Idiot]

Back button removes the focus from the shutter so you can focus and recompose without having the camera refocus.

 

[Big Mike]

ETTR is a good method for getting the least amount of noise in your images. If you look at the first/older article on L.L....the title is actually something like 'maximizing the s/n ratio'. The s/n ration is the Signal to Noise ratio. The premise is that the noise in an image is constant, but the amount of data, brightness (signal) isn't. You can have bright images, dark images and of course you can have areas within you image that are bright/dark/mid toned etc. The brighter the image (or part of it) the more data there is...or you could say 'the more signal' there is.
So because the noise is constant, we can look at the ratio between the level of noise and the level of signal...the s/n ratio.
In the brighter areas (more signal) the s/n ratio is higher...so we see less noise. In darker areas, the s/n ratio is lower, so we see more noise.

So if we take that and apply it to our photography, we end up with the Expose to the Right technique. By overexposing our photos, we are getting a higher average s/n ratio across the whole image....resulting in less visible noise.
So if you want to shoot with the least amount of noise, then this is a good technique.

Of course, with digital photography, truly blown out detail is lost and not recoverable. So you have to be very careful about not overexposing the photo to the point where you are blowing out the highlights.

I think that a good lesson to take from this, is that you should avoid underexposing your images, especially at higher ISO levels...because that will give you a very low s/n ratio and lots of noise. And if you try to brighten an image in post, that noise gets brightened as well and you get a terrible looking photo.

As for the back button focus, that is something I've been doing for 5 years now. On my older cameras, I set the custom function to all the * button to activate focus, rather than the shutter release button. Now they have added an af-on button back there, which is great.
I wouldn't say that it will give you 'more accurate' focus, it just allows you to separate the focusing from the shutter button, which may mean that you miss-focus less often.

 

[Derrel]

Kerbouchard's second post is pretty complete on ETTR; one of the most-critical aspects of ETTR is that the histogram's graphing and the "blinkies" will be created from an in-camera JPEG that reflects the Tonal Curve and Saturation Levels the camera is set to...so...if for example the image saturation and the Tonal Curve are cranked up high, the histogram and the blinkies will indicate over-exposure sooner (with LESS exposure) than if the Tonal Curve was set to Low (for Low-contrast) and the color saturation was set to Normal as opposed to High.

The unibal or uni-white balance idea has caught on only among the most-critical workers. It's difficult to find much information on it, but there is some out there.

As far as the light meter question: a case can be made that a calibrated light meter, used by an experienced worker who has a knowledge of his/her sensor's actual dynamic range, might be able to ETTR a bit better than a person relying on the histogram. Sekonic has a fairly new light meter that the user can "program" with the camera's response to various exposures, and can set up I believe it's three different films or cameras into a memory bank that will allow you to "push" right to the "real" limits, without being fooled by histograms based on JPEGs, or on the "blinkies". This meter relies upon ACTUAL TESTING to establish the "real" capabilities of the sensor. Kind of making it a tool that would be familiar to old-school, pre-digital commercial and studio photographers used to exposing expensive film, destined for expensive processing, for demanding clients.

One of the things that we now have, and which we didn't have in 2003, is "highlight recovery" in software...back then, RAW image converters were pretty crude...pretty lame, really. SO, if ETTR back then was more-necessary due to narrower dynamic range of those older d-slr's, back then the SOFTWARE that would allow quick and easy recovery of over-exposed highlights was JUST coming into its own...

 

[Derrel]

Back-button focusing: the professional level Nikons have an AF/ON button as well as an AE Lock button, closely positioned, and programmable in many different patterns, for customized user set-up. "Other" camera makers used a " * " button for over a decade, then decided to copy Nikon's idea and call it a "focusing button".... kind of funny...

Yeah, back-button focusing has some real plusses, in that it separates the focusing operation from the shutter release button. That can be a good thing sometimes. But it does require the user to be in the game for it to work.