24-70 L IS Problem, does this look right?

[BlueTit]

I have never being happy with this lens and find I take the 28-135 out more instead, so I did a quick test. The camera was on Tripod, MUL & Remote release.

The centre focus spot is centred on the middle box, the middle box is 12 feet from the camera and the two box on either side of the centre are approx four inches in front and three inches behind respectively.

24-70 lens at 70mm 1/25s f5

http://photos15.flickr.com/22225875_2ecd2b23b6_o.jpg


28-135 lens at 75mm 1/10s f5

http://photos17.flickr.com/22225924_fba98791b1_o.jpg

If there is a better or more accurate test I could do, please let me know.

[kawter2]

If there is a better or more accurate test I could do, please let me know.


I would shoot at least 1/90th

[BlueTit]

I would shoot at least 1/90th

Ok to use flash then? or wait for daylight, but that means weekend as I am not home anyday this week in daylight :(

[Marvinspu36]

You don't say what type of camera you are using. Assuming you are using one of the Canon EOS digital cameras, you should focus on the text on the box. If your center focus point is centered on the box as you suggest, this may be your problem. The Canon AF system requires contrast to focus. So it will not focus well on solid colors. The center of the picture is on the solid white portion of the box. Try placing the center focus point over the letters on the box. This should help quite a bit.

The above is true regardless of what lens you use. Also, your shutter speeds are way to low. As suggested, use a faster shutter speed, espescially if shooting hand held. Pick a shutter speed that is at least the same as your focal length. That is, if you are shooting at 70mm, shoot using a shutter speed that is greater than 1/70s. I generally use a shutter speed that is twice the focal length if possible.

[grego]

Your test is kinda conflicted in that you have different focal lenghts and different shutter speeds.

[richardho11]

Also, the 24-70 is at 70mm vs. 75mm. Which means that the boxes in the 24-70 photo should be smaller if they are both cropped at 100%. But in the photo that you are presenting, the 70mm photo of the boxes are indeed closer (bigger). Seems like you cropped the 24-70 at 115% vs. the 28-135 at 100%.

[tim]

Do this test (http://www.canon-dslr.com/Canon_Jan05/Canon_SLR_Focus_Test.htm), on a tripod, mirror lock up & cable release, or maybe use the timer if you don't have cable. Do the test 3 times for each lens, both at the minimum focusing distance for the lens, and and a moderate distance. Once that's done you won't need our opinions, but i'll happily give you mine if requested.

[ssim]

The 24-70 has IS??

[Nightcrawler]

I would buy it in a heartbeat if it did.

[ddelallata]

I almost felt stupid for not knowing that they had IS. :)

[BlueTit]

SSIM, sorry about the "IS" in the thread title, I was thinking of the 28-135 which I was using in the test too :-( Jasonhuebert: I wish it did.

Marvinspu36, thanx for resurecting this thread again, I thought it had died. It also serves to remind me that I have not adequately tested this lens for once and for all, so I am going to do that now.

Tim. Thanx for that link I will do that, it looks like it will tell me one way or the other if I have a problem or the lens.

I will report back on how I get on.

[malla1962]

The 24-70 has IS??no.

[BlueTit]

I have not had time to do Tims test yet, I printed off the test sheets, but have not had the light to try it. In the meantime I used this lens for about 300 shots yesterday evening and got a few nice ones but a lot are terrible, this is a screen capture from EOS Viewer to show where the single centre focus point was. This is only a small section of the phot, the whole looks just as bad, but it does not look like camera shale to me, there is no "double vision" or "trails", as you can see it was 1/50 secs in fairly low light, but it was also 24mm, so handheld should have been ok? What I am really asking is, Is this bad focus or camera shake or do I still need to do Tims comprehensive test to see if it is a focus problem. BTW there appers to me to be no area in the whole photo that is in focus.



http://photos23.flickr.com/26924900_6a67edd589_o.jpg

[remo]

Shutter speed 1/50. Could be camera shake......

[Salleke]

I have not had time to do Tims test yet, I printed off the test sheets, but have not had the light to try it. In the meantime I used this lens for about 300 shots yesterday evening and got a few nice ones but a lot are terrible, this is a screen capture from EOS Viewer to show where the single centre focus point was. This is only a small section of the phot, the whole looks just as bad, but it does not look like camera shale to me, there is no "double vision" or "trails", as you can see it was 1/50 secs in fairly low light, but it was also 24mm, so handheld should have been ok? What I am really asking is, Is this bad focus or camera shake or do I still need to do Tims comprehensive test to see if it is a focus problem. BTW there appers to me to be no area in the whole photo that is in focus.

BLUE Tit - Sorry for saying it and don't take it as an offense. But IMHO no one can hold this lens steady at 1/50 sec even at 24 mm.
I have had one and had the same problem. Take e few pictures handhold at 1/50 and then at the same speed with tripod and with
the selftimer. Even at 1/125 it's difficult to handhold the camera/lens steady.

Do this test: focus at a subject and watch the center focuspoint and concentrate at watching your subject at one point and see if you can hold your centerfocuspoint on that point whitout moving at all. I'ts like aiming a rifle. You will see that we can not hold this camera and lens steady. And ad the movement in to account of your finger/hand as you push the shutter. Don't forget that it's a heavy lens. Only whit tripod or monopod you can be shure to have no camera or handshake.

[BlueTit]

Salleke, no offence taken. I have just never being happy with this lens, but have no had time to test it properly so I was hoping someone would just say bad lens and that would be problem solved. If you are correct, the lens is just not as versatile as I hoped and I will have to put more effort in when I use it. Thanx for your opinion. I promise I will do the full test this weekend and that will tell me what I need to know - just to lazy and too busy :-(

[CyberDyneSystems]

@ 1/25th.. the IS on the other lens could be the whole difference..
1/25th hand held is not conducive to sharp images

[SolPics]

I had similar issues as far as not getting proper focus, but it was me and not the lens. I now either increase the shutter speed or the ISO if I want to keep the same aperature. The lens is phenomenal as to its optical quality, the sharpness and the depth of color. It's just heavy for its focal length and not the easiest to handhold.

[Croasdail]

You should be able to hand hold an IS lens at 1/50... why else buy an IS lens. But I do agree, this is lens shake, not focus. If you don't have a tripod or time, try pumping up the ISO so you can have a higher shutter speed. Image may get noisy but youll be able to see if focus gets better.

[SAZABI]

~_~ 1/70 at least... well... depends on what focal length...

I agree with the 1/90 to be safe :)

[blue_max]

You can soon tell if it is camera shake - shoot a few test shots at 1/50 and then some faster. If it improves, you have your answer. I wouldn't start blaming the lens at that sort of shutter speed.

Graham

[jimchapin468]

I own this lens and to get sharp images I would try shooting a shutter speed of 100 or more.