 Meghan Gonski |
Lenses Hello, I was wondering why some lenses extend when when focusing and some extend when zooming and some don't extend at all. I have a fantastic lens by canon 70-200mm f/2.8 that does not extend at all. I love that. Anyway, one of those lenses is an L series and the other one according to reviews online is pretty close to an L series. It seems like they would make these non-extending like my 70-200mm f/2.8 lens.....?
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Lynn R. Powers |
Meghan, You are reading the chart wrong. They both extend from the lower number to the larger number. Many of today's lenses were designed long before digital DSLRs were even thought about. The 24-70 f2.8L is one of them. Canon decided there wasn't a need to change to full internal focusing on the lens because of R&D costs as well as passing the additional cost to the customer could reduce its popularity. Rare earth glass, internal focusing and zooming, constant minimum f stop at all focal lengths and IS/VS are all items that increase the prices on lenses. Sometimes the size of the lens prevents certain alternatives to be viable. The EF-S 17-55 f2.8 is designed to be used on crop cameras only. The "L" designation, Luxury, only goes on EF lenses which are designed for full frame cameras as well as crop cameras. Unfortunately for us the customer the price for all the lenses to have the features, except for weight, of the Canon 70-200 f2.8L IS would be exorbitant.
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- Carlton Ward Contact Carlton Ward Carlton Ward's Gallery |
I have the 24-70mm f/2.8L and you are correct as this lens zooms out when shooting at 24mm and shortens when shooting at 70mm. The 3 lenses I carry everywhere are the 24-70, the 70-200mm f/2.8L IS & the 100-400mm f/4.5-5.6L IS and that lens is a push-pull zoom. I have owned the 100-400 the longest and though it is a bit of a light-hog and the push-pull can get a little dust but I do love this lens. When set to f/7.1 the subject is tack sharp and the background is beautiful. The 100-400 weighs the same as the 70-200 f/2.8 but when zoomed out to 400mm - people notice :) I will soon replace my 17-40mm f/4L with the 16-35mm f/2.8L or preferably the 14mm f/2.8L - if I can afford that one :) I started with a 20D but knew I would eventually go full frame so I built my lens collection as Lynn mentioned because the EF glass works on either APS-C or full frame. I have heard positive things about the 17-55mm lens but have no tried that one. Here is one of my favorite pics with the 100-400 called "Bad Hair Day". This EMU was trying to peck me and the hard light on his head, the detail of the crunchy stuff around his eye and the little hairs/feathers are sharp. The background wall was kinda ugly gray w/crap on the walls but the f/7.1 DOF made it look very blended. Cheers, Carlton
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