Is there something wrong with my camera?

dubcat

dubcat

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Name
Amir
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My 17-55 2.8 needed +8 micro adjustment on my 50d to focus right.
The 50mm 1.4 Sigma lens I bought today needs +10 micro adjustment to focus right.

Does my camera need recalibrating? Would there be any advantage in getting that done or should i just micro adjust it for each lens and leave it at that?

Thanks
Dub
 
Is it only those two lenses that are out or are they your only ones so nothing else to go on? My Sigma 50mm f1.4 is out by 6 points and I have one lens that is something like 16, however my Canon 24-105 and 70-200 are both spot on. As the latter is the case I'm going to be sending the Sigma 50mm in for calibration with my 5DmkI as that doesn't have Micro Adjust so currently isn't really usable.
 
I will do some tests on my other lenses but they don't go to such a shallow depth of field in the case of the 10-22. My 4th lens is the 70-200 f/4L. I will check on that.
 
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mark1616 said:
I wouldn't worry about the 10-20 as you won't see much, but the 70-200 (I'm guessing that's what it is) will show what is going on.
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Yup soz it is the 70-200. You are right - i should check it out. Will try to give it a go tomorrow.
 
You've got +/-20 so I shouldn't worry. That's what it's for.

How are you testing it? How close is the target?
 
HoppyUK said:
You've got +/-20 so I shouldn't worry. That's what it's for.

How are you testing it? How close is the target?
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Target is a £20 note stuck to a window. It is about 200cm from the camera. Camera is set to max aperture, mounted on tripod and connected to a laptop. Using the camera remote software I have a magnified view of the camera in live view mode. I set focus to quick mode, hit af-on and then use the little arrows to get a picture better. The number of arrow clicks is the amount of micro adjustment I dial in. I then rinse and repeat until I get the best picture right away without any adjustment needed.

I like to use the bank note because the watermark really helps to compare different settings at. I did not repeat the test as many times as I wanted to due to time constraints but i think it is an improvement and will refine further later.
 
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Isn't that too close? I'm sure the amateur photographer testy charty thing that they gave away suggested a minimum of 100 x the focal length so it would be 100 x 70mm = 7000 mm or 700 cm for the 70mm end and much further for the 200mm end.
 
srichards said:
Isn't that too close? I'm sure the amateur photographer testy charty thing that they gave away suggested a minimum of 100 x the focal length so it would be 100 x 70mm = 7000 mm or 700 cm for the 70mm end and much further for the 200mm end.
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This was for a 50mm lens. I read it should be 50x. I was probably a little too close still but if I go further away it is hard to see the watermark.
 
Should be a min of 250cm if you're working to 50x. Perhaps you need to find something better to focus on that could be managed from a greater distance more easily? An A4 sheet with big writing on might be easier.
 
dubcat said:
Target is a £20 note stuck to a window. It is about 200cm from the camera. Camera is set to max aperture, mounted on tripod and connected to a laptop. Using the camera remote software I have a magnified view of the camera in live view mode. I set focus to quick mode, hit af-on and then use the little arrows to get a picture better. The number of arrow clicks is the amount of micro adjustment I dial in. I then rinse and repeat until I get the best picture right away without any adjustment needed.

I like to use the bank note because the watermark really helps to compare different settings at. I did not repeat the test as many times as I wanted to due to time constraints but i think it is an improvement and will refine further later.
Click to expand...

2m is a little close, but should be okay. It needs to be at a sensible distance - a representative shooting distance. If you test too close, in order to create artifically shallow depth of field to see changes more clearly, the system will be at the edge of its operating envelope and the danger is that if you make corrections then, it could make things worse at normal range.

The other problem is with angled test targets, such as many that you can download from the web or as given away with Amateur Photographer magazine recently. The AF sensor is larger than shown in the viewfinder and with an angled target you can never be sure exactly what distance it is locking on to. The only way to absolutely guarantee that is with a flat target, set square to the camera. Something like a £20 note stuck to the window/wall is okay - anything with some fine detail.
 
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