Small RAW, any noise or diffraction reductions?

[rcsenn]

<p>OK, I have my 50D and like it a lot, but I am strugging a bit with my 300mm F4 and 1.4x combo. On my old XTi I would shoot at an F-stop higher and be OK without percievable diffraction, but now I'm trying to not go over F8. Good chance that most of my problem is camera shake, but I thought I had enough shutter speed, (I was shooting wildlife, and really didn't want to use a tripod). This got me to thinking though about something I think I read concerning another company's reduced pixel mode being aimed at reducing noise in high ISO, or something to that effect. Now with a 50D, what are the chances of using the lower RAW settings and seeing a reduction in the high ISO noise, or being able to go to a higher f-stop before diffraction starts to be objectionable. <br>

I'm not a professional photographer, physist or anything close but I'm just guessing here that the easiest way to try this out is take some shots with the settings where I feel that the noise and-or diffraction is starting, in standard RAW, then changing only the RAW to the smaller RAW taking some shots and comparing.<br>

I also think that the final output size will be reduced in the smaller RAW setting, so 100% is not equal to 100% on screen, but if final print size is equal then that is what should be compared. <br>

Please feel free to point me in whatever direction as needed.</p>

<p>Richard</p>

[harold_motte]

<p>If you use sRaw that will help reduce noise, however the file size will be smaller.<br>

Also, if I remember right but you will want to search this. If you also turn off highlight tone priority and have settings on standard or faithful with reduced sharpening in camera that will also help reduce noise in the Canon 50d.<br>

I had one when they first came out but got rid of it due to its high noise problem especially with me shooting a lot of indoor high school gym sports. The 7d is way better. Had to use Noise Ninja a lot with that 50d.<br>

There are a couple of articles about what I mentioned but I did not save them. Google it and you will probably find them. They could have been on the Canon forums, I can't recall.<br>

Best Wishes</p>

 

[scott_ferris]

<p>Diffraction has nothing to do with it, the diffraction is exactly the same on your 50D as it was with your 30D(?). The fact that the pixel density can display that diffraction more accurately is not the issue, the adverse effect of it on your images is the same.</p>

[ken schwarz]

<p>Richard -- Take a look at the thread from a few days ago called "Megapixel antidote". If you reduce your resolution to that of your old XTi, you should get at least as good if not better noise for a given ISO setting using your 50D.I found that using the SRAW setting gives you pretty much the same reduction in noise as you get by reducing resolution in post-processing. SRAW is handy if you need to squeeze more images into your flash rom card or you want to shoot more frames in rapid sequence without filling up your buffer.</p>

[rcsenn]

<p>Thanks for the responses. I was pretty sure that it made more sense in my head than once it got out.<br>

Harold, thanks for the info. I'm getting there with the settings like you are suggesting, and I'm not really displeased about it. I wanted the 7D, but someone upgrading to a 7D let me have the 50D at a price below what I'd seen a few 40D's go for, so I took it; no regrets.<br>

Scott, thanks, and like I posted above it was making more sense to me before it got out of my head. <br>

Ken, Thanks for pointing me that way. I seemed to miss that thread, and my search keywords did not catch it.<br>

Richard </p>

[g dan mitchell]

<p>You'll get exactly the same amount of diffraction at a given aperture with both systems.</p>

<p>Dan</p>

[steven_f1]

<blockquote>

<p>Good chance that most of my problem is camera shake, but I thought I had enough shutter speed, (I was shooting wildlife, and really didn't want to use a tripod)</p>

</blockquote>

<p>The general rule of thumb for 35mm and full frame is to use a shutter speed that is the reciprocal of the focal length lens. So a full frame camera with a 85mm lens you should have a shutter speed of at least 1/85 of a second. For APS-C cameras you need to take into account the crop factor of 1.6 for the XTi or 50D you would need a shutter speed of at least 1/136 of a second (1/(85x1.6)). for a 300mm lens without IS use a shutter speed of 1/480 of a second or higher. With the 1.4 extender use a shutter speed of 1/672 of a second. The extender changes your F4 lens into a F5.6 lens. This may make it hard to get sufficient shuttter speed. </p>

<p>Some people have very steady hands and may get buy with less. Others may need even more shutter speed. I am personally quite close to this rule of thumb although I generally prefer an extra 1/2 stop to be sure. I have found for IS lenses (with IS on) I get sharp photos at a shutter speed 2 stops slower than indicated by this rule of thumb. Turn off IS when using a tripod.</p>

<p>While diffraction can be a concern above F11 it may not always be noticable. If I need it I will use F22. What is worse an unacceptable photo or one slightly degraded by diffraction?</p>

<blockquote>

<p>but I am strugging a bit with my 300mm F4 and 1.4x combo</p>

</blockquote>

<p>Extenders generally will degrade the image somewhat. Although I haven't used a 300mm lens with an extender I would guess your problem is probably a combination of insufficient shutter speed and the extender. Try your lens without with and without the extender with it attached to a tripod to determine how much of an effect the extender has. Alsoexperment with shutter speeds above and below the above mentioned shutter speed rule of thumb to determine how much shutter speed you need.</p>

[michael_p.1]

<p>Slight digression. " Turn off IS when using a tripod."<br>

How should one handle a monopod. I use a monopod with the Canon 100-400. It is not nearly as stable as a tripod but... Should IS be turned off? </p>

[michael_p.1]

<p>Slight digression. " Turn off IS when using a tripod."<br>

How should one handle a monopod. I use a monopod with the Canon 100-400. It is not nearly as stable as a tripod but... Should IS be turned off? </p>

[steven_f1]

<p>I haven't done much with a monopod but I would leave IS on in that case. Although you might want to experiment with one shot with IS one without for a day to get a better idea if it will work. In my eperiments with a tripod most IS problems occured between 1/20 of a second and a couple of second. During daylight hours you generally can get a high enough shutter speed to avoid the problem exposure areas with still enough motion in the camera for the IS system to track. </p>

[scott_ferris]

<p>Any movement and leave IS on. That means always on a monopod and most times I leave it on when on a tripod too. Unless the tripod is very good and firm then there will be movement the IS can take out.</p>

[craig_meddaugh]

<p>Yes... everyone should check to see when IS becomes problematic with YOUR tripod and head. Takes a couple minutes and will save you heartache in the end. </p>

<p>As for the OP... diffraction is diffraction. Higher resolutions let you (1) observe diffraction sooner and (2) allow you to magnify the image more. Both aspects will make higher resolution images look softer when viewed at 100%. You should compare the prints. I think you will find the results surprising.</p>

<p>Also, if you are concerned with diffraction ruining your images, you should definitely be using a tripod. The lack of stability is far worse than any of this diffraction nonsense cooked up on the internet. </p>

<p>Finally, sRAW will reduce noise as pixels are being averaged, but you can perform a similar averaging with any image editor software. I've heard apocryphal tales that the sRAW images are ever so slightly better than simply averaging the pixels yourself in post, but I have seen no evidence of this in my own work. </p>