Lens problem

…. i have to say that digital SLR lens’ focal lengths are different to the old manual SLR cameras that came before. So although it was a 300mm in fact it was comparable to a 400 (ish) mm lens of old. So my new Canon 70 – 250mm lens is more than suitable for what I need. And it has built in stabilizer so cuts out (or down) any camera shake. AND it wasn’t as expensive as I thought it was going to be. Got it from Argos. Check them out.

😀

Tony.

Hi Tony,

Its not the lens “length” that is different it is the camera sensor, on the “smaller” Canon DSLRs (anything from the EOS1000D up to and including the EOS 7D body IIRC) the digital sensor “crops” the image as compared to a 35mm negative body fitted with same focal length lens. The crop factor is approx 1.4x, so a 70 – 250mm zoom (as it would be known in 35mm film days) effectively becomes a 98 – 350mm lens on your EOS 600D.

This is useful ‘benefit’ when the camera/lens is used for airshows etc, though it does mean that even a 35mm wide(r) angle lens acts like a 50mm did in “old money” which can be bloomin’ frustrating in cramped spaces – to get a 35mm lens effect as you would have got on a film SLR you need a ca. 25mm lens on the EOS 600D body. Hope this makes sense?

I have the sister Canon 70 – 300mm IS lens (used for around five years on my old EOS 350D body and more recently a 40D body), I agree they give good results for the money they cost. I would recommend against using them at maximum zoom, as the images tend to go a little soft, I find it better to zoom out a little, and then crop the image on the PC later, seems to give a sharper end result. Canons IS Image stabilisation system really does work too, definitely allows me to shoot two shutter speeds lower than without it – though it does tend to use up battery charge quickly make sure you have a spare battery handy.

Also, as was mentioned in the thread earlier, try to set the camera so that it stops the zoom lens down to maybe F11 or more if you are using it at it’s longer zoom lengths, this helps keep images sharper too.

Paul F

Although we have decided, i think, that is was not camera shake i have to say that digital SLR lens’ focal lengths are different to the old manual SLR cameras that came before. So although it was a 300mm in fact it was comparable to a 400 (ish) mm lens of old. So my new Canon 70 – 250mm lens is more than suitable for what I need. And it has built in stabilizer so cuts out (or down) any camera shake. AND it wasn’t as expensive as I thought it was going to be. Got it from Argos. Check them out.

😀

Tony.

I tend to agree, having had a good look again. As has been stated, a lense may have been displaced in the array.
Jim.
Lincoln .7

If it were camera shake, the unsharpness would have been on the same side all over the picture. The detail shots clearly demonstrate the opposite.

I.M.H.O. It was Camera shake, perhaps a higher shutter speed MAY have solved the problem.
I have been a great Canon fan for years, and I am fortunate to have most of my prime lense fitted with I.L.S. and have never had the same trouble as you describe.
I am no David Bailey, just point and shoot, where the I.L.S. comes in handy. But unfortunately, one has to save up ones pennies.
Jim.
Lincoln .7

I ended up getting rid of the lens in question and went for a Canon zoom lens. No problems there at all.

Tony.

This thread just explained a problem ive been getting with the same lens 🙂 cheers guys

It might be a good idea to take your test picture using a tripod. Also stop the lens down to f8, 100ASA and take the picture in better light – most lenses perform at their best in sunlight at lunchtime in summer.

Regards

great forum

eco tech

Dunno what the point of your quality shots are ???

The point was to see what the shadowing on the image was.

“The “Shadowing on the bunting” looks like motion blur to me ? maybe the bunting was moving in the wind?”

Yes, I thought that at first but the shadowing is exactly the same on the writing on the sign and the window frame behind. Now I have read about Chromatic Aberration I can see that is the problem here. I will send that lens back, get a Canon and do the same test again. Watch this space.

Tony.

I’ll read up on the Chromatic Aberration to get a full understanding but if it was camera shake (at 500th?) the shadowing would have been on the same side of objects at either side of the picture depending on which way the camera was travelling during the shake.

I will also read the lens review.

Thanks for all your comments so far.

Tony.

Just to clarify Tony, the possible camera shake has caused softness
not the CA the ca is down to the lens itself.

The “Shadowing on the bunting” looks like motion blur to me ? maybe the bunting was moving in the wind?

( He shot at 1/500th, which could introduce a bit of camera shake),

I’ll read up on the Chromatic Aberration to get a full understanding but if it was camera shake (at 500th?) the shadowing would have been on the same side of objects at either side of the picture depending on which way the camera was travelling during the shake.

I will also read the lens review.

Thanks for all your comments so far.

Tony.

For one thing the CA is visable in a Huge crop, The quality of the image is about right for the quality of the lens, so I guess we should agree to disagree 🙂

Dunno what the point of your quality shots are ??? you can get sharp shots at 1/500th I agree, but in this case the poster hasn’t (In my opinion)

I would’nt say the Chromatic Aberration is excessive for this lens.

I tend to disagree, as the aberration already is very obvious in a relatively small print. This kind of performance is unacceptable in any modern lens.
Here’s ( http://www.photozone.de/canon-eos/592-tamron70300f456vceosapsc) a review of a Tamron 70-300mm lens. Especially note the positive comments on the level of chromatic aberrations. The performance figures at f/8 and f/11 at the 300m end are almost identical.

Below an example of a good quality 300mm lens at f/8, handheld at 1/500sec.

100% detail

A degree of Chromatic Aberration is noted in reviews of the Tamron 70-300mm zoom, however the shooter may improve the problem by shooting a lower iso, F11, and higher shutter speed ( He shot at 1/500th, which could introduce a bit of camera shake), he probably wont achive all this at together so should keep the f11 and low iso and use a tripod, or rest the camera to keep steady, the posted image looks soft.
I would’nt say the Chromatic Aberration is excessive for this lens.

An explanation of Chromatic Aberration can be found here http://mansurovs.com/what-is-chromatic-aberration

Unfortunately the rather extreme chromatic aberration shown in the pictures is not going to be resolved by either a lower ISO and/or stopping down even further.

Could you explain that “chromatic aberration” please?

Unfortunately the rather extreme chromatic aberration shown in the pictures is not going to be resolved by either a lower ISO and/or stopping down even further.

Try stopping down to around f/11 as well… although to be honest it should be slightly sharper than that at f/8.0…

Zeb

You’ve shot that at 800 iso, try 100 iso and compare the results.