Focus Question

Andrew Davies Photography

Andrew Davies Photography

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OK folks a quick ( or long if you want ) answer of people in here if possible just to settle an issue i am having with a lens sale.

Would you expect a Canon 50mm 1.4 usm lens to nail focus on a low-mid range canon body on the OUTER FOCUS points at F1.4

Or would you either stop it down a little or use manual focus / or recompose to make sure of focus
 
I have that lens... and I can tell you my experience with it. It was crap on my 7D, disappointingly soft all round at 1.4, 1.8... it was only really pin sharp around 2.8, which is where I ended up having to use it most times. When I moved it to a FF, all things improved significantly. So yea, now, after my experience, I would expect it to be soft and would never try to use it wide open. Don't know if that helps or not... but just my experience with that particular lens.
 
Me too however after selling my 50 1.4 on fleaebay the buyer has opened a case because it wont focus on outer focus points accurately when shooting test targets at 1.4 :rolleyes:

Have offered to take it back but they are insisting its faulty so i have to pay for return postage which under the circumstances is a bit stupid for me , I remember now why i cant stand fleaebay !!
 
Selling on eBay, the buyer has all the cards. Take the hit on postage, you might be right but you'll never win.

It doesn't matter how many expert opinions you get, the arbitrator is someone who wouldn't know the difference between an EF 50mm 1.4 and a table lamp.

Sell it on here, where at least the person buying it is likely to know a bit about photography and have realistic expectations.
 
The lens doesn't care (or know) which focus point is used, it's just commanded to a position based on a calculation by the body. If the body can't cope with a mediocre lens then that's a different matter.

Bob
 
Ok so the buyer is claiming that the lens is forward focusing on outer points and accurate on the centre point only when used at 1.4, to be honest i would not dream of trying to use outer points at 1.4 but thats just me ! Especially considering a lot of the time you are at 1.4 or wide open because its low light in which case the outer points are going to be poor at best , on my 5d3 and the 1dx they have more cross points but i would still expect it to struggle
 
Well, forward focusing on the outer points while being accurate on the centre one. Claim that it is a camera fault (the problem is between the AF sensor, mirror, and actual image sensor) and the lens has nothing to do with it. Maybe it is just clearer to him now that he is using f1.4 with such a shallow depth of field.
 
The problem here is the growing hobby of amateur lens testing. Guys (it almost always men)who buy these lens test charts will test the crap out of every lens they own and they expect each and every lens to produce super pin sharp images at all apertures
 
Upper end bodies have micro adjustment for a reason. I had the 50mm 1.4 and it was never great on my 7D, better on my 1D iv, but shone on my 1DX.
I wouldn't want to use an outer point at f1.4, but as above the buyers expectations are above the capabilities of the body.
 
i would be asking if he has another lens with a f1.4 aperture to compare it to eliminate the possibility of it being the body or if centre af point is used is the image sharp overall
if the answer is yes when centre af point is used then the problem lies with focus and not the lens

but like others have said were talking about ebay and buyer is king
 
Id ask if he's tried focusing manually, with the outer area zoomed in on live view.

If he can get it focused, it's easier to blame the body.

At f/1.4 though? As others have said, the expectations here are unrealistic.
 
Phil V said:
Selling on eBay, the buyer has all the cards. Take the hit on postage, you might be right but you'll never win.

It doesn't matter how many expert opinions you get, the arbitrator is someone who wouldn't know the difference between an EF 50mm 1.4 and a table lamp.

Sell it on here, where at least the person buying it is likely to know a bit about photography and have realistic expectations.
Click to expand...

^^ This - get it back and move on.
 
After some converstaion he has realised its not that straight forward and decided to keep the lens and work on it :) all's well , I think we probably all go through this stage the first time we get a prime lens - its a real eye opener just how crap your technique is and then you move forward leaps and bounds.
 
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