Why Exposing to the Right (ETTR) is BAD!

Started Mar 30, 2013 | Discussions thread
Barrie Davis
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Re: Why Exposing to the Right (ETTR) is BAD!
In reply to schmegg, Apr 1, 2013

schmegg wrote:

Barrie Davis wrote:

schmegg wrote:

JulesJ wrote:

apaflo wrote:

Barrie Davis wrote:

What puzzles me (actually, I am completely mystified) is why people seem incapable of associating exposing to the right with the consequent loss of film speed  (using an effectively lower ISO). I have had long ping-pong type exchanges in these forums with posters who just could NOT accept that THAT was what was happened. Quoting the actual shutter speeds and apertures USED at them just didn't help, because they didn't associate THOSE with any particular ISOs, either, it seems.

Why is that, do you think?

Because what you just said doesn't make any sense at all???

Explain why you say that Apaflo. A criticism is no use without an explanation of exactly what you mean.

The reason I bought in was because this statement ...

"people seem incapable of associating exposing to the right with the consequent loss of film speed  (using an effectively lower ISO)."

That clearly does not make a whole lot of sense. And it took me a while to even work out why he made this statement.

I think what is being claimed is that an exposure adjustment must be made to expose the sensor for longer - and in this one way only it's analogous (perhaps) to shooting with a lower ISO. But in every other respect, unless the ISO setting is used to vary the exposure shift, then the ISO setting is irrelevant to ETTR. So the claim above is largely irrelevant and seems to just introduce unnecessary confusion to the topic IMHO.

See what I mean, Jules? From the above it becomes clear...

There are an awful lot of people that can't a get a grip on the idea that overexposing a 400-ISO shot by one stop's worth of ETTR is precisely the same (that is, employs same shutter speed and aperture) as exposing at 200-ISO...

..... and therefore IS using 200-ISO..

No - it's not using ISO200 at all - not if the camera is set on ISO400!

That's where you are completely wrong.

However, I have already stated that I am not going to ping-pong postings on this matter. That is a pointless exercise. It is my opinion that if anyone does not understand this absolutely fundamental fact about the exposing of photographs, then it's likely they never will.

Moreover, if you, personally, ever get there, say, with somebody else's help, then GREAT...

.... but it isn't going to be my efforts that do it. Sorry. You must make your own arrangements.

A sensor does not have a variable sensitivity - it's sensitivity is fixed. ISO is achieved by applying gain to the readout - and the higher the ISO setting, the higher the gain. That's it - nothing more.

So, if you expose at ISO400, then the gain applied is the same as if you ETTR at ISO400.

If you expose at ISO200, then the gain is different.

.....that is to say, there isn't the slightest photographic difference whatsoever.

I don't know whether to consider this state of affairs funny, or just rather sad... 

I'm not sure why you need to be so derogatory about this discussion.

As I said, perhaps I have misunderstood the gist of your point. But, based on what you've said above, then it would seem that your statements, at the very least, are a bit misleading.

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Regards,
Baz
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"Ahh... But the thing is, these guys were no ORDINARY time travellers!"

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