[Rob Barron]

I wouldn't normally do this but I feel the validity of this test was poor due to using internal lighting that has caused variations which were probably not down to the lens so I am taking new photos outdoors and will repost here ASAP.

I entirely agree with the comments that there shouldn't be as much difference as is being shown by the colour picture and I want this test to be useful to people. Be back soon!

Cheers,
Rob

[silver]

are you using a tripod,.

the book cover with the 50 lens has some kind of colour cast going through the middle of it,,. either not a good subject or you need to light it differently

if the zoom beats the 50 on sharpness with both @ f8 then you either have a v bad 50 or there's something else v strange going on...

Sil

PS, I thought canons mid range zoom was the 24-70L - just curious..

[Rob Barron]

Silver,

It is because of that strange artefact that i am doing the pics again in natural light tomorrow but they were both taken at exactly the same time without ever moving the camera, the subject or the lighting.

There is nothing strange going on that the zoom is sharper than the prime because of the quality of the optics. The L series is massively more expensive optics so despite being a zoom is still extremely sharp.

The mid-range zoom NOW is the 24-70mm but that is an upgrade from the original 28-70mm lens. You surely don't think I am going to sell mine and buy the new one, losing a couple of hundred quid in the process, just to gain an extra 4mm? I already have the 17-40mm l series so the wide end is covered with that lens.

We'll have another look at the sharpness and resolving power tomorrow with brightly lit outdoor shots.

Cheers,
Rob

[silver]

just curious,. I have the 24-70L I didn't even know they did a 28-70

are you using a tripod (pref w. mirror lockup),. to test a lens sharpness you need to use one,. unless you are testing IS / your handholding technique

Sil

[Rob Barron]

I used a tripod, RAW mode and as minimal processing as possible. Just resizing and made the colour temperature 2750 for every shot for direct comparison.

They introduced the 24-70L about a year or so ago, maybe two. The 28-70mm lens was always the standard zoom people went for if they wanted L series quality. I would have gone for the 24-70 if buying more recently for sure but not going to change as there are other lenses I would still like.

I am considering a 10-22mm but am holding off to see what sensor size the 40D has as I shall definitely be buying that camera when it comes out (assuming it is a sensible upgrade of course but I am certain it will be as I have the 20D, not the 30D.

I didn't use mirror lock-up but that isn't essential if the tripod is good and stable. I did use remote release, not manually pressing the shutter.

Anyway, let's see what the results come out like tomorrow.

Cheers,
Rob

[silver]

it's interesting because your result goes against the commonly understood viewpoint (well mine at least) about standard prime lenses,. the contrast might be slightly higher on the L but at f8 even that I would have guessed is quite close..

Sil

[Rob Barron]

There are prime lenses and prime lenses. Whilst the nifty fifty is a very good lens and one everyone should have in their bag, L series lenses don't cost a bomb for nothing. Yes, prime lenses are better than zooms when comparing like with like. So for example my 300mm IS L series should be sharper than my 100-400mm IS L series when used at 300mm (I am going to be doing a comparison on that pair soon.

I have three zooms and 3 primes and it has to be said the zooms are rapidly catching up these days. The quality achievable with top notch zoom lenses really is excellent.

Cheers,
Rob

[silver]

zoom lenses are generally not as sharp as primes,. unless the prime is very poor

I went and looked at the canon MTF charts and the 50 should be sharper - at least that's how it looked to me comparing the 24-70L against the 50 1.8 II - which is to be expected

Sil

[Dave]

An interesting test Rob, as it goes the opposite way to what I experinced here :- Budget prime vs Premium Zoom vs Pro Zoom lens In these tests the 50 was marginally better than £1000 optics from Nikon, used & raved about by the pro's.

One thing on the tests I ran, was the shots all came out pretty much the same in terms of colour, where as you seem to have a difference in yours ? Mmmmm

Although I do not doubt the L lens glass, the difference you are seeing does make me me wonder if you have a duff nifty there ? Even if the L glass was better, I would question if you should see such a big difference in image quality ?

Looking forward to some natural light tests

[Steve]

I have used both of these optics (extensively) and can confirm that my results were opposite to what your findings have shown here. In my opinion either the test is flawed or you have a very bad version of the 50mm.

First of all you need to remove as many variables as possible. Irrespective of how good your tripod is, in a test like this you simply have to use mirror lockup. It will totally remove any possibility of camera shake and externally introduced blur thus giving both lenses the same point to start from. The lighting used seems dark and to be suffering from colour casts, I understand you use RAW format but here again in a controlled environment you should have manually set the white balance for each of the lenses prior to the photos being taken. As you say each lens has different optics and they use different coatings which will alter and change the colour casts reproduced.

Finally as I was not present and this test I cannot even begin to guess at what has caused the discolouration in the centre of the 50mm book cover shot. If you didn’t change anything at all in the setup then your 50mm is definitely not working as designed. My 50mm has never caused any discolouration unless shooting into the sun and those results would have been the same for any lens used in that situation. There is definitely something wrong here.

Like Dave I’ll look forward to your follow up test but I am really having trouble understanding how you can believe your conclusions from this test.