Canon 70-300 USM IS extremely unsharp

[charedan]

<p>See <a href="http://focustestchart.com/chart.html">http://focustestchart.com/chart.html</a> to see how to test for front/back focussing issues.</p>

[grzegorz_szczotka]

<p>http://dl.dropbox.com/u/4019776/2010_04_19/focus%20chart.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8844.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8845.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8846.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8847.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8848.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8849.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8850.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8851.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8852.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8853.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8854.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8855.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8856.CR2<br>

http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8857.CR2</p>

[charedan]

<p>Hi Grzegorz,<br /> The focus chart shot is easier to help in determining focus accuracy. The sample shot you uploaded with no AF adjustment shows that the bottom 2mm and 4mm lines are in better focus then the center line and that therefore your lens is front focusing. The curtain shots are not as easy to judge good focus.<br /> Also, try to get more light on the chart so that other factors such as low shutter speed, high iso or noise does not effect outcome in order to better judge focusing accuracy and making better adjustment.<br>

IS to off on sturdy tripod should also help.</p>

[grzegorz_szczotka]

<p>http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8860.CR2<br>

Taken with better light, iso 400, sturdy tripod, IS off</p>

[grzegorz_szczotka]

<p>And even better: http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8862.CR2</p>

[grzegorz_szczotka]

<p>The best one ;)<br /> http://dl.dropbox.com/u/4019776/2010_04_19/IMG_8870.CR2<br /> Daylight (1/1250, iso 200)</p>

[koot_marais1]

<p>Grzegorz<br>

I hope you get acceptable results. I was extremely dissapointed with my 70-300 IS and eventually sold it. It seems sharp when you shoot something closeby in good light (i.e. newspaper on a wall), but when the subject is far away and light conditions are not ideal, it is impossible to get a photo that is up to standard.<br>

My lens was not back- or frontfocusing so I could not correct it with microadjustment. I tested the lens against my 100-400, my 70-200 f2.8 and 70-200 f4 (the last two with 1.4X converter) under the specific conditions and the 70-300 was not close to the other lenses.</p>

 

[fezmid]

<p>I can't see the photos you posted -- the links don't work due to too much traffic.<br>

That said, did you turn IS *OFF* before taking the shot? Since you're on a tripod, IS will actually make the pictures blurry. I learned that the hard way.... :)</p>

[grzegorz_szczotka]

<p>Photos are here:<br>

http://szczotka.net/photos/<br>

Yes, the IS is off</p>

[w_t1]

<p>Raw files aren't supposed to be sharp, but you already know that, right?</p>

<p>I downloaded raw file 8845, it looks about like any other raw file that comes from my 40d or 5d or 1d2 prior to post processing/sharpening. </p>

<p>It's like the others have said about the focus points, it's not rocket science. I've missed some shots using AF with the above cameras that I was sure I nailed, but didn't. If it's really critical use MF. I use it about half the time with my 300 f4 is lens. And set the CF to focus with the thumb.</p>

<p>Maybe you're expecting too much out of your equipment - the raw file i downloaded was shot with a continuous light, the shawl with the plant. I never would use autofocus for a still life like that, but bottom line is it looks to be in focus, and needs sharpening applied for intended purpose.</p>

[grzegorz_szczotka]

<p>W T, a quick introduction to sharpening raws using DPP? Just using sliders "sharpness" ?<br>

I am beginner ;) Thanks</p>

[jim_krupnik]

<p>The basic RAW page on the floating DPP toolbar allows you to adjust sharpness from the standard setting selected for each picture style. I would suggest that you look at a 100% view of an area in the file while you tweak sharpness. It's difficult to really judge the changes at less than 80% or so. Remember, you don't modify the RAW image at all, so you can't kill it if you go overboard with tweaks. Just back them off, and start again.</p>

[w_t1]

<p>Grzegorz, search here or in the "digital darkroom" forum. post processing & sharpening are like opinions, everyone has one and they're all different.</p>

<p>Canon website is a good source of info, and there are video training links for dpp online.</p>

[grzegorz_szczotka]

<p>So, to sum it up. Does this lens have front focus or not?</p>