Dual-ISO -> Alternate frames only: Take 2 shots by single shutter button press

Started by Walter Schulz, April 11, 2015, 03:53:43 PM

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Walter Schulz

Hi!

Low priority: Would be fine to have an option to take both shots by a single shutter button press.
There is a related option in Shoot tab -> Shoot preferences -> Pics at once
but  this will work for "intervalometer, motion detect, trap focus, audio remote" only.

garry23

@Walter

You can get close to what you are asking for by using the intervalometer, together with the dual setting.

It's not perfect, eg stop after 2 gives me three images, stop after 1 gives me 1.

It's also only usable on a tripod, because of all the delays.

Audionut

I'd rather see the alternate option removed.  Force people to consider if they really need dual ISO or not.

tron

@Audionut: Alternate option is very useful. It encourages people to use Dual ISO more often.

Why should we choose one or the other? We cannot be sure on the spot of DUAL ISO results.



Audionut

Quote from: tron on May 21, 2015, 02:52:09 PM
@Audionut: Alternate option is very useful. It encourages people to use Dual ISO more often.

Dual ISO should be used as needed, not more often.


Quote from: tron on May 21, 2015, 02:52:09 PMWhy should we choose one or the other? We cannot be sure on the spot of DUAL ISO results.

http://www.magiclantern.fm/forum/index.php?topic=12096.0

tron

Quote from: Audionut on May 26, 2015, 07:50:03 AM
Dual ISO should be used as needed, not more often.
http://www.magiclantern.fm/forum/index.php?topic=12096.0
You cannot know 100% unless you see the final DNG and compare it to a normal processed RAW photo.
1. Resolution 2. Possible Artifacts (OK very rare and are dealt with crhdr.exe updates) 3. Any other issue that may happen.

In summary, it's best to have the best of both worlds. I cannot see why the capability should be removed. If someone feel they do not need it they are free not to...

Audionut

Quote from: tron on May 27, 2015, 11:49:23 PM
You cannot know 100%

If you cannot know, that's fine.  Don't paint everyone with the same brush.

tron

I did not know that people are psychic and can know in advance the results of dual iso crhdr processing...

dmilligan

If you understand how cr2hdr works and realize that it is a deterministic computer program with a predictable output, then yes it's possible to have a reasonable idea of the results (resolution, artifacts, "any other issue", etc) in advance.

garry23

Not wishing to get in the middle of an e-conversation, i offer this personal view:

* Dual ISO is a killer ML feature, but made better by two other ML 'killer features', namely RAW-based ETTR and RAW spotmeter.
* If you don't have an eye for dynamic range, all you need to do is use the very accurate ML spotmeter, ie narrower than a classic 1 deg spot on most lenses, and meter the DR of the scene, thus helping you to gauge the need for Dual-ISO;
* Finally, with ETTR and sensibly managing speculars you can, with Dual ISO, maximise the DR capture.
* Finally, if on a tripod, you can fall back on auto-bracketing, by first metering off the darkest areas you wish to see details.

Bottom line: ML tools are there to help you,not substitute for your knowledge.

Just my humble view.

tron

1. There are cases at the limit. Wouldn't someone want to take advantage of full resolution?
OK this is ETTR stuff more or less  but:

2. There are some cases that are DR or as I said at the limit but at the same time are once in a lifetime (or at least in what I have in mind) once in a year. I would like to have the best of both worlds in case something goes wrong.
(I am talking about full moon rising behind temples for example which by the way I will try to shoot in a few days   :D  )
There are many combinations depending on the specific moonrise, sunrise times that make it normal or DR. I am talking about the full moon day, the previous day is a typical non-DR scene where in fact sometimes the moon can be barely seen due to sun and the next day being at the limit because although dark there are artificial lights turned on.

3. Finally, I cannot understand the empathy against shooting alternate pictures. Does it harm the experts to have this feature disabled if they are not interested in it?

Audionut

If you only had a film camera, would you expose correctly the first time, or just fire off a bunch of random shots and see which shot worked best?
In the digital world, we have the greater luxury to just fire off a bunch of shots.  Such a shame the digital methods don't force the user to increase his knowledge as quickly as with the film method.

And finally.  I shared a singular opinion on the matter, no more, no less.  Next time I should just label the thread as WONTFIX, really get those knickers of yours in a right royal knot.

tron

DONT FIX JUST DONT BREAK...

By the way when I had a one time chance to shoot a total solar eclipse with a film camera I bracketed a lot (keeping the 500 rule) during the 2.5 min totality phase using Fuji ISO 200, an EOS1n with 300 4L + 2XII fully open at f/8. Guess what: I succeeded :-)

By the way during the partial phase I was able to make just one exposure selection (using a solar filter) since I was able to shoot a roll one month before and decide what I want in advance.

But I guess if you were there with a film camera you genius would expose totality correctly with just one shot  ;D ;D

P.S The situation I described 2 entries before is also a 2 minute event and every time the dynamic range is different due to the difference in moonrise and sunset times.