Those "in-between" ISOs...

[Mark Elberson]

Add ALO into the mix and you can get people wondering why their ISO 250 shot looks like ISO 1600.
<div style="CLEAR: both"]</div>

What are your thoughts on ALO (Auto Lighting Optimizer)?


How about the "Tone Curve Assistant" in DPP?

[Daniel Browning]

What are your thoughts on ALO (Auto Lighting Optimizer)?

ALO and the tone curve assistance are nice. ALO doesn't affect the raw file (it's just metadata), and I use it when I'm shooting video to get a little more highlight headroom. But for stills I don't use it because I prefer to have more direct control of the tonal values and contrast myself.

[Chuck Lee]

Which 'tweener ISOs are less bad and which ones should be avoided?

160,320,640, &amp; 1250 are the good ones (DB would say "more acceptable") You can emulate these as follows:


160 = 200 + .3ev; 320 = 400 +.3ev; 640 = 800 +.3ev; &amp; 1250 = 1600 + .3ev (I call these the +.3ev tweeners)


125,250,500, &amp; 1000 are the bad ones (DB would erase you from his friends list.. LOL [])You can emulate these as follows:


125 = 100 - .3ev; 250 = 200 -.3ev; 500 = 400 -.3ev; &amp; 1000 = 800-.3ev (I call these the -.3ev tweeners)

is any of this relevant to amateur photography?

I would say yes. It is why I stated that "ISO160 is as good as it gets on the 40D." I made this statement, unfortunately, without listing any qualifiers which started the whole tangent over 100 vs 160.


If the camera is on a tripod and I have setup my 40D or 50D to shoot +1 to +2ev ECand I am trying with all of my intelligible talent and top end RAW conversion softwareto soak every last drop of noiseless dynamic range out of my exposure thenDaniel is correct that ISO 100 is better than ISO 160.


If I am handholding the camera, letting it meter the lightand am maximizing the shutter speed and/or the aperture then I believe ISO 160 is the best you can get in terms of a low noise image on the 40D. I could have done the exact same thing by shooting at ISO 200 +.3ev EC. The difference for me, the Missouri amateur, (even though I'm from VA)is that I don't have to think about. That's the amateur part. If the settings are available, why not make use of them?


So, ask yourself, would you rather shoot at ISO100, f4, 1/80th or ISO160, f4, 1/125th using the camera's metering? And the ISO 160 photo at these settings will be cleaner. I find it a simple "no brainer"


In pondering the discussion this morning it dawned on me that until the 5D MkII these +.3ev tweeners only offered an enhanced lower noise effect on the XXD "crop" sensor bodies. You can see on the Ruevski Sitethere is no advantagefor the 5D. If you take into consideration the increased zoom effect that 1.6X sensors create it parallels the increase in shutter speed that the +.3ev tweeners offer. For all practical purposes for the amateur it compensates for the extra reach of the lens. Following the focal length reciprocal rule you get:


200mm @ 1/200th on 5D FF@ ISO100


200mm(320mm equiv.)@ 1/320 on 40D @ ISO160


I find this very "practical" and very simple for the amateur photographer to follow.


Hope this helps.............[]

[Fast Glass]

But why did Canon say that larger pixels have better noise? Acording to Canon larger pixels colect more light, requires less amplification, there for less noise.The wayI seeit isliketwo shallow dishes of the same depth but one is say 40% larger,and put it out side when raining.Which will have morewater, the lager one. In retrospect it's the same thing in sensors,the more light the pixel well collects in a certain amounttime,the less it needs to be amplifed.Canon confirms thishere http://media.the-digital-picture.com/Information/Canon-Full-Frame-CMOS-White-Paper.pdf.


I am missing something here?

[Daniel Browning]

But why did Canon say that larger pixels have better noise?

Since this thread is about tweener ISO settings, I thought it would be a good idea to respond to your question in a different thread:


http://community.the-digital-picture.com/forums/p/1055/14445.aspx#14445