Photography Thailand Forum

[Marc Schultz]

The attached photo was taken last year as a test shot with the 1DS Mark II and an older Canon 28-70mm zoom at F/4.5. The first photo shows the full frame image and the next two photos are some close-up crops of it. The 3rd of the 3 images is not in focus as the sharpest focusing point when the photo was taken was on the water drops, but this close-up of the flowers shows you just how much detail is captured by the lens and the camera overall.

The lens used was an older model Canon 28-70mm zoom, which has now been discontinued and replaced by the newer 24-70mm lens released by Canon within the last 2 years. The actual lens this shot was taken with was manufactured in 1998 and there have been some further advances in lens optic technology on the newer 24-70mm lens since then. There has been no manipulation done on this photo. Please judge for yourself:

[yish]

First I would be misleading to hold canon as a bench mark for the sharpness of lenses.
While I have not used the 70-200 I have used many types of gear in my work as a professional photographer. I have found that all the SLR zoom lenses were not sharp.
Now I do not know Michael Reichmann, however I do know enough professionals and even people who have had custom lenses made by Schneider kreuznach in order to have exact sharpness performance they required.

I have not needed to do so for my work (or the budget), however I do know what a sharp image looks like.

yishay

[Marc Schultz]

If we are discussing the sharpness of zoom lenses, I think the professional line of Canon zoom lenses, meaning their L series zoom lenses, are as good as any for making a comparison on sharpness between zooms and primes which is the topic of discussion here at the moment. As for your findings, I am sorry, but I for one do not share in your general opinion about the sharpness of SLR zoom lenses. If you can provide either some technical or visual examples to help support your statements about SLR zoom lenses never being sharp it would be helpful for everyone I think.

Also "SLR zoom" lenses can refer to medium format lenses as well, and I just want to clarify that my opinions in this discussion are based upon 35mm SLR zoom lenses. Best wishes.

[David Salmanowitz]

Anna--I guess I forgot you already had the 24-70mm lens. Get the 70-200mm IS lens as with those two lenses you can cover a lot of ground. BTW, with the 70-200mm you will not be shifting from shoulder to shoulder--you will more likely be hunchbacked.      I have to pack as I am off to the Philippines tomorrow AM, but here is a quick shot with the 70-200mm IS and the Canon 1.4 teleconverter as well--used on a 20D last year so you can see the quality the lens is capable of. Probably better quality was possible but this is just with a tad of sharpening (I think, as I have changed my post photo routine as I learnt some mistakes I was doing), nothing else was done. Note the monkey hidden in the background--not the same one that hit me (you do  not want to know where, thought it was very entertaining for all who were watching). I think the monkey felt threatened by the long lens and teleconverter.

[Marc Schultz]

David's right, weight is surely a consideration with the 70-200mm as compared to any of the shorter zooms.

If you don't mind breaking your back, and the bank, the 28-300mm lens is a one stop lens that covers every range.

Well, even if possibly out of the typical price range, have a look here. A lot of photographers when doing travel photography prefer it so they don’t have to keep changing lenses. It is very convenient because you can go from short to long range in a flash (no-pun intended) and the reduced number of lens changes on-location will minimize the amount of dust getting onto your sensor.

http://www.dpreview.com/news/0401/04012901canon28300is.asp

[David Salmanowitz]

Mark--I could be wrong and technology is changing as we speak, but I always thought a lens covering as wide a range as the 28-300 would have a "sweet spot" and fall off at other focal lengths. Still could be very good and if one shot within the sweet spot range no problem, and even out of the range could still be acceptable--though not as good as within the range. Having lugged a backpack full of heavy lenses the idea of just one lens (but it is not a tilt/shift or a macro) is very appealing, but I still would opt for lugging the lenses. What I do not like about the 28-300 is that it is a push/pull lens, versus a twisting lens. Just seems more accurate, quicker, and with a better feel to have a lens that I can twist thru the focal lengths rather than pushing and pulling.

[Marc Schultz]

It would be worth reading some reviews on that lens to find out if what you say is true about a sweet spot and having some fall off after that. I have held it several times, but I have not shot with it so I can not give you any first hand accounts on picture quality. There seems to be a bit of useful chatter about it here though:

http://www.photographyreview.com/cat/lenses/35mm-zoom/canon/PRD_299753_3128crx.aspx

It is a popular lens though and for $2,500 I am sure Canon has put a lot of money into optical development on that lens. The price is not expensive compared to some of the Hasselblad MF primes I have bought which can go much higher in price, but for a Canon lens it is probably their most expensive.

I can also say that I prefer the rotational zooms rather than the pump barrel type. I have the 100-400, which is also a pump (push pull) zoom action lens and it is not as easy to control as a normal type zoom. The barrel has a ring which you need to lock when you are not using it or the zoom will fall out if you have the camera over your shoulder, which makes a bit of bang on the inside of the lens housing and probably not so god for it over the long term if you do that often. But probably Canon has a reason for this design, I just have not adjusted to it well, but I normally don't use it more than once or twice a year since I don't do any sports or bird photography to speak of, so I have not had much chance to really get used to it.

To be quite honest, the lens I use probably 90% of the time for everything is the handy, light weight 24-105mm F/4 L IS lens, which is not even an F/2.8 lens. In fact, I can't remember the last time I shot anything at F/2.8 anyway, but that is just my shooting style. Most often I control overall depth of field with the telephoto affect of the lens and distance from my subject when shooting and the difference between F/2.8 and F/4 for me is of no net effect.

Without getting into too much of a lengthy discussion here about lens apertures, I find F/2.8 risky for me anyway. If I focus lock and move the camera just a little bit at F/2.8 with a full frame sensor DSLR, which is how I shoot a lot of the time, then I can almost guarantee you the intended focal point will have moved.

[silvero]

I can sympathise with what the OP is experiencing, but I have one 'back-to-basics' suggestion that might help a bit before diving into a new lens.

Why not put the camera into aperture-priority mode, change the AF settings so that it only uses the middle spot for focusing, and then doing a whole bunch of test shots.  Using the middle spot ensures you pick the focus distance, and aperture-priority mode means you can pick a range of apertures to see the DOF results for different aperture settings.

Pick a a scene where you can see at a range of distances what is in or out of focus, then shoot at a bunch of different apertures, then examine the results at 100%.  Soon after I got my camera I thought I had a faulty lens, but of course it was the operator that was faulty and this is how I got to grips with focus and DOF.