Question about "full" iso stop

troika · 09-12-2014, 05:52 PM

Well, it kind of did. Someone suggested that there may or may not have been an issue with Canon.

We could all test it, but I'm not aware of an issue on Pentax. I shoot in Tav mode a lot, which frequently results in partial ISO stops.

normhead · 09-12-2014, 06:35 PM

There's no reason to only use full stops.... does that help?
I think everyone is a bit speechless, just trying to fathom the concept.
I mean there was a time stops were holes in a circle that could be rotated so different sized hole acted as aperture openings. In those days, you had to use full stops, there were no half stops, only a hole for each full stop. I can't imagine anyone here goes back that far unless is would be dadipentak or someone like that.

Oldbayrunner · 09-12-2014, 06:50 PM

Let me end my part in this with a quote from Normhead, as I in my 56 years of photography find this pretty dead on;

Originally posted by normhead

To every suggestion, an exception, learning to expose isn't about following rules. It's about learning to get what you want from an image.

**Rondec** · 09-13-2014, 03:29 AM

I just think he's wrong with regard to the full stop thing. There isn't any particular reason to shoot only at iso 200 and 400 and not at the in between isos. As you go up in iso, there will be more noise and less dynamic range, that goes without saying, but the idea that you should only go up by full stops seems silly.

My experience is to just use the lowest iso you can and still get a sharp photo with a good exposure. Exposing to the right is something I only do at really high iso -- above 3200. Otherwise, I expose for the highlights and bring up the shadows in post.

dtmateojr · 09-13-2014, 03:54 AM

In-between ISOs resulted in weird interpolations that will actually degrade your shots. I don't exactly remember how but I think it was something like this: If you shoot at 250, the camera actually shoots at 400 and adjusts back to 250 during processing. You don't gain anything in terms of noise but you risk clipping the highlights. Don't quote me on this. Not sure if this is still true with more recent cameras.
Anyway, I only shoot in full stop ISO and aperture increments. I let the camera handle the shutter speed unless I shoot in full manual mode in which I just shoot in full stop increments as well. It just makes exposure calculations a lot easier for me.

---------- Post added 09-13-14 at 20:58 ----------

An unrelated "feature" is that of dynamic range optimisations in camera. Notice that if you enable this feature you can't set your camera to the base ISO. If your base ISO is 100, the lowest you can set is 200. This allows the camera to underexpose ALL your shots to save the highlights and then push the shadows in processing.

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09-12-2014, 05:52 PM	#16
troika Pentaxian Join Date: Dec 2012 Location: Seattle, WA USA Posts: 1,753	Well, it kind of did. Someone suggested that there may or may not have been an issue with Canon. We could all test it, but I'm not aware of an issue on Pentax. I shoot in Tav mode a lot, which frequently results in partial ISO stops.

09-12-2014, 06:35 PM	#17
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	There's no reason to only use full stops.... does that help? I think everyone is a bit speechless, just trying to fathom the concept. I mean there was a time stops were holes in a circle that could be rotated so different sized hole acted as aperture openings. In those days, you had to use full stops, there were no half stops, only a hole for each full stop. I can't imagine anyone here goes back that far unless is would be dadipentak or someone like that.

09-12-2014, 06:50 PM	#18
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	Let me end my part in this with a quote from Normhead, as I in my 56 years of photography find this pretty dead on; Originally posted by normhead To every suggestion, an exception, learning to expose isn't about following rules. It's about learning to get what you want from an image.

09-13-2014, 03:29 AM	#19
Rondec Loyal Site Supporter Join Date: Mar 2009 Location: Gladys, Virginia Photos: Gallery Posts: 27,652	I just think he's wrong with regard to the full stop thing. There isn't any particular reason to shoot only at iso 200 and 400 and not at the in between isos. As you go up in iso, there will be more noise and less dynamic range, that goes without saying, but the idea that you should only go up by full stops seems silly. My experience is to just use the lowest iso you can and still get a sharp photo with a good exposure. Exposing to the right is something I only do at really high iso -- above 3200. Otherwise, I expose for the highlights and bring up the shadows in post.

09-13-2014, 03:54 AM	#20
dtmateojr Veteran Member Join Date: Jan 2012 Photos: Gallery Posts: 604	In-between ISOs resulted in weird interpolations that will actually degrade your shots. I don't exactly remember how but I think it was something like this: If you shoot at 250, the camera actually shoots at 400 and adjusts back to 250 during processing. You don't gain anything in terms of noise but you risk clipping the highlights. Don't quote me on this. Not sure if this is still true with more recent cameras. Anyway, I only shoot in full stop ISO and aperture increments. I let the camera handle the shutter speed unless I shoot in full manual mode in which I just shoot in full stop increments as well. It just makes exposure calculations a lot easier for me. ---------- Post added 09-13-14 at 20:58 ---------- An unrelated "feature" is that of dynamic range optimisations in camera. Notice that if you enable this feature you can't set your camera to the base ISO. If your base ISO is 100, the lowest you can set is 200. This allows the camera to underexpose ALL your shots to save the highlights and then push the shadows in processing.