Testing sharpness

Ruffy

Ruffy

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Paul
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I have just brought a brand new Canon 100-400L, I have heard some good and bad points and I have noticed a fair few threads popping up on here just recently too.

What I would like to know is, whats the best way for testing for sharpness, settings etc etc, would like to take a few shots and post them up for advice on its sharpness !!

Thanks in advance

Paul
 
We have a thought at our club, as long as the photographs are good and you are happy then this sort of test and similar ones are just an ego boost, if you see it is sharp than what more.
 
JSER said:
We have a thought at our club, as long as the photographs are good and you are happy then this sort of test and similar ones are just an ego boost, if you see it is sharp than what more.
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Well thats the problem, i am not sure and I dont know the best way to test it, I have just spent over £1200 I have a right to seek that help and advice and how would it be an ego boost when all i want to do is make sure my lens is working as it should, the shop have offered a replacment if its soft !!!

Thanks for the help :shrug:
 
I would set it to high quality JPEG with moderate sharpening and go out and take some photos ensuring that the shutter speed is at least equal (if not greater) than the focal length you're using.

Take a variety of shots, landscapes, buildings (brickwork is often a good test shot), maybe a bird, people etc at various apertures/ISOs (depending on the the light you have available).

If YOU think any of them don't look sharp, post them up on here with the EXIF intact and ask for people's opinions.

If you google you'll be able to find plenty of test images to take pictures of but as JSER eluded to, you could be on a hiding to nothing going down this route ;)

I bought a pre-owned 100-400 from MPB, the first thing I did was go out and take some pictures. Luckily I live right near the beach and managed to get some seagulls and other birds in flight along with some more "general" shots which you can see here http://www.talkphotography.co.uk/forums/showthread.php?t=306518 The general concensus seems to be that my lens is a good copy so you could compare your shots with my shots for starters :)
 
If you are talking purely about sharpness then you need to eliminate 3 things:

Camera movement - you should shoot from a tripod in completely vibration free conditions with mirror lockup and a shutter release.
Movement of the target - Shoot static subjects, preferably high in contrast and detailed such as a text chart or newspaper
Focussing errors - you should manually focus to prevent the camera front or back focussing.

Dont shoot at apertures smaller than f11 or diffraction will set in. Try a range of focal lengths. Shoot RAW.

That would be the crux of a more technical sharpness test. You have to eliminate as many variables as possible
 
Ruffy said:
Well thats the problem, i am not sure and I dont know the best way to test it, I have just spent over £1200 I have a right to seek that help and advice and how would it be an ego boost when all i want to do is make sure my lens is working as it should, the shop have offered a replacment if its soft !!!

Thanks for the help :shrug:
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As I said, quite right and I fully 100% agree with you, no hesitation, you want to see that what you have bought is perfect, what I was saying is that, and here is an example.

A few months ago a magazine printed a test chart, someone at our club who has been winning competitions and has been 100% contented with their lens tried it and was extremely upset, it showed his lens was "off".

In fact within tolerence and nothing to concern anyone, ever since they have been niggled by the lens.

Can you see what I mean, just because a "lab bench test" may show a "fault" does not mean ther is a problem don't get upset by the results.
 
Presuming your camera has liveview you could lock it down to tripod and take a variety of subjects by focusing manually. It is best to try with detailed distant objects. Try to AF, and then see if it improves by adjusting manually through live view. This will tell if AF is doing the best job, or should be microadjusted.
Try focusing with the centre and then recomposing the subject to either side. Is the sharpness maintained? If not I would think about returns here.
How does it compare to other know-to-be-good lenses? You may find that 400mm is slightly soft, however anything to 300mm should be very good. If it isn't - return it.

You have paid enough to have a good copy, and also if canon sells junk they need to get a good lesson for that. If it's soft please return it while you can.

I know far too many people think that L means 'best' regardless, and ignore the real sharpness (or lack of) or simply can't focus properly. I am trying to buy something on ebay and find it nearly impossible due to terrible attitude of the sellers.

edit: keep shutter speed well above 1/500s or better 1/1000s for all tests. Even the shutter action is enough to cause shake. Use mirror lock up.
 
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Thanks guys (and JSER, misunderstood what you were saying,lol)
 
Whan shopping on ebay I have learnt.

I write....

"Please can you inform me of any fault the item has, is it in 100% perfect working order".

I have just this week bought an item described as good condition and fully working.

When it arrived a lead was "cut" and the item was faulty, not working, he even said and I quote "the lead was ok when it left me", and has JUST stated he may have snagged it a year or so back.

I have a full refund but and now taking him for the return postage too.
 
how do you find the exif sorry for the hijack ive heard it mentioned and know its the information about the shot how do i find it tho
 
If you are shooting with a UV filter on the 100-400 the IQ might seem a little soft. I had a good quality UV filter on mine for about 6 weeks before I took it off and put the lens hood on for protection instead. The IQ difference was amazing, it had gone from disappointing to amazing in 5 minutes flat. I only use a filter on it now if I'm shooting in an excessively dusty, sandy or wet conditions and then I know the IQ drop will be worth the added protection.
 
Ruffy said:
I have just brought a brand new Canon 100-400L, I have heard some good and bad points and I have noticed a fair few threads popping up on here just recently too.

What I would like to know is, whats the best way for testing for sharpness, settings etc etc, would like to take a few shots and post them up for advice on its sharpness !!

Thanks in advance

Paul
Click to expand...

The problem with buying a new lens is that your expectations may well exceed your skill until you learn exactly how to use your lens to get the best from it.

I've generally found that each lens is different in the way you have to use it.

When I first got a Canon 100mm macro (non IS) I was dismayed to find the very low percentage of keepers I was getting from it.

It was only after an analysis of the problems the answer was apparent - the problem was ME!

I was so used to using IS lenses that using a non IS lens at macro closeness meant that even tiny amounts of camera blur were enough to spoil the shot.

After that I found that as long as I used a tripod or a very high shutter speed or flash the number of keepers went way up.

And don't forget that even IS won't stop all camera shake especially at 400mm or so and slight subject movement can also produce a "soft" image.

And PP is also important - I always use 0 sharpness in camera on my shots (JPEG) then apply sharpness before resizing and as a final finish once resized and before saving (and if that upsets the purists among you well I'm quite happy with my results and to me that's all that matters).

And I think my pictures are very acceptable sharpness wise.

.
 
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