Hi I was just wondering...
I use a 20D + 500mm IS lens + 1.4 TC and a huge manfrotto tripod plus arca B1 ball head and sidekick. For flash I use a a Wimberley flash Bracket combo 6 for my 550 EX and Better Beammer.
My problem is that I cant get enough sharp images. Many times the focus is about 2-3 cm closer to me than were the autofocus selector point is locked on the subject or the images are moved at speeds ranging fron 1/100 to /1000
I gave the lens plus camera to Canon service and they told me the system was OK...
So my question is what are I`m doing wrong?
Is there any tech for shoting with long lens?
I always have to lock the sideckik before shotting?
I heard that some people hold the lens with presure downwards to eliminate vibrations...is that true?
Is better to use MF with this system? or AF is better?
I feel the sensor of the 20d many times has trouble selecting the exact distance-subject point when the red AF point pops.
Well if someone can help me with this issue I`ll apreciate it a lot.
When I use my 500 and 1.4 TC along with my 1DMK2 I hardly ever lock the ball head down as I am moving it to follow or reframe a subject a lot. I get consistantly good AF. Yes, sometimes I lock down and use my arm to steady the system when using long shutter speeds of about 1/100 or less (at 700 effective focal length). However, most of the time this is not necessary with the IS. I know I didn't answer your question, but you shouldn't be having this issue.
A suggestion si to borrow another body and use the lens and TC on it to see if the issue still exists. If not, your camera is front focusing and should be again recalibrated by Canon.
Hi Pablo
The short answer to your question is that there is some technique to shooting with the longer lens. The longer answer is this. First, set up a test shot of a static subject where you can set your tripod on solid ground or pavement, lock down your ballhead, rest your left arm on the balance point of the lens and press your eyebrow against the camera eye piece to add your own mass to that of the lens. Do some test shots using autofocus and also manual focus to be sure that the 2 of them agree. Repeat this whole procedure with the 1.4 TC as well. I suggest you do this at an ISO of 400 with an aperture of f8 to start. If you're not getting tack sharp images this way then go on to the next test.
If as you suspect the camera and lens are front focussing, set up a small object like a pin on a table top with a ruler or meter stick laying beside it so that you have the scale of the ruler parallel to the axis of your lens (pointing at your lens). Your camera and lens should only be slightly higher than this test setup. Now with everything locked down and as solid as possible take some shots of the pin. If your lens is front or back focussing you will be able to see that on the rule an see where the focus point actually is.
My 1DII and 500 developed this problem after a couple of years of use. I found my bird images were only sharp to the eye of the bird (small birds particularly) and that the rest of the head was soft. When I did this test it became apparent that the lens was front focussing 2 cm which is quite a lot with a long lens. Canon was able to take the lens and camera combination and recalibrate it and it's been fine for the last 2 or 3 years now.
Ok I did the tests following eds suggestions...
Sharp images :P
The only thing I found is that the focusing selector point (Eos 20D) sometimes focuses on wrong targets :S
I set up three pins on a table with distances of 1cm from each one and did the test with the ruller.
Supposing the AF point was in the middle pin I got sharp focus on the back pin, this was random getting focus sometimes in the front pin.
Using MF I didn´t have problems.
So Ok I´ll send back my camera to canon service and see what they tell me.
Regards,
Pablo Rodriguez.
www.art-natura.com.ar
Posted by Dave Larkman on July 26, 2006 at 12:49 PM
Hi Paublo
If you are taking pictures of static objects do not use the AI Servo. This might help.
Discussion
5 repliesI use a 20D + 500mm IS lens + 1.4 TC and a huge manfrotto tripod plus arca B1 ball head and sidekick. For flash I use a a Wimberley flash Bracket combo 6 for my 550 EX and Better Beammer.
My problem is that I cant get enough sharp images. Many times the focus is about 2-3 cm closer to me than were the autofocus selector point is locked on the subject or the images are moved at speeds ranging fron 1/100 to /1000
I gave the lens plus camera to Canon service and they told me the system was OK...
So my question is what are I`m doing wrong?
Is there any tech for shoting with long lens?
I always have to lock the sideckik before shotting?
I heard that some people hold the lens with presure downwards to eliminate vibrations...is that true?
Is better to use MF with this system? or AF is better?
I feel the sensor of the 20d many times has trouble selecting the exact distance-subject point when the red AF point pops.
Well if someone can help me with this issue I`ll apreciate it a lot.
Regards from Argentina,
Pablo Rodriguez.
www.art-natura.com.ar
A suggestion si to borrow another body and use the lens and TC on it to see if the issue still exists. If not, your camera is front focusing and should be again recalibrated by Canon.
Good luck.
The short answer to your question is that there is some technique to shooting with the longer lens. The longer answer is this. First, set up a test shot of a static subject where you can set your tripod on solid ground or pavement, lock down your ballhead, rest your left arm on the balance point of the lens and press your eyebrow against the camera eye piece to add your own mass to that of the lens. Do some test shots using autofocus and also manual focus to be sure that the 2 of them agree. Repeat this whole procedure with the 1.4 TC as well. I suggest you do this at an ISO of 400 with an aperture of f8 to start. If you're not getting tack sharp images this way then go on to the next test.
If as you suspect the camera and lens are front focussing, set up a small object like a pin on a table top with a ruler or meter stick laying beside it so that you have the scale of the ruler parallel to the axis of your lens (pointing at your lens). Your camera and lens should only be slightly higher than this test setup. Now with everything locked down and as solid as possible take some shots of the pin. If your lens is front or back focussing you will be able to see that on the rule an see where the focus point actually is.
My 1DII and 500 developed this problem after a couple of years of use. I found my bird images were only sharp to the eye of the bird (small birds particularly) and that the rest of the head was soft. When I did this test it became apparent that the lens was front focussing 2 cm which is quite a lot with a long lens. Canon was able to take the lens and camera combination and recalibrate it and it's been fine for the last 2 or 3 years now.
I hope this helps Pablo. Let us know how it goes.
Sharp images :P
The only thing I found is that the focusing selector point (Eos 20D) sometimes focuses on wrong targets :S
I set up three pins on a table with distances of 1cm from each one and did the test with the ruller.
Supposing the AF point was in the middle pin I got sharp focus on the back pin, this was random getting focus sometimes in the front pin.
Using MF I didn´t have problems.
So Ok I´ll send back my camera to canon service and see what they tell me.
Regards,
Pablo Rodriguez.
www.art-natura.com.ar
If you are taking pictures of static objects do not use the AI Servo. This might help.
Dave