 Heather McCrory |
New Zoom Lens I currently have a 55-20mm zoom lens and I would like to get something much stronger, but of course am on a budget. Are there any stronger lenses out there that won't brake the bank? Also I have seen some of the larger ones that are manual focus only, are these worth the money at all? P.S. I have a Canon Digital Rebel if that helps
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Jon Close |
Canon EF 75-300 f/4-5.6 (with or w/o USM), Tamron 70-300 f/4-5.6 LD Macro and Sigma 70-300 f/4-5.6 DG Macro are all pretty similar and good values at less than $200. A little better optics is the Sigma 70-300 f/4-5.6 APO DG Macro for ~$200. These are plenty long on the Digital Rebel. Re the manual focus only lens, I assume you're looking at 500 f/8 mirror lenses. While I have one of these (actually I found one that is f/5.6) and like it, I would only recommend it as an addition to a 70-300 zoom, but not instead of one. Besides manual focus, these have a single aperture only, "weird" doughnut shaped background blur, and really need to be used on a tripod to eliminate camera shake.
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Heather McCrory |
Thanks for the respose. The manual ones I was talking about are more the 600mm-1000mm or something like that. What about those?
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Jon Close |
Like this one? They aren't mirror lenses, so don't have the doughnut background blur, but otherwise are similar. It is basically an inexpensive telescope with an adapter to attach it to a camera. The aperture is not adjustable, it simply changes with the zoom setting. There is no lens/camera communication, so metering is restricted to M and Av modes only. f/8 and smaller leave a relatively dim viewfinder, making focus a challenge in all but the brightest light, and require very high ISO settings to get action stopping shutter speeds. And such long focal lengths require use with a steady tripod. And they tend to have a simple optical design that is not well corrected (commonly suffer from chromatic aberration, ie. "purple fringing"). That said, these are a good alternative to hobbyists who don't have several thousand dollars to spend on a very sharp, large aperture autofocus lens like the EF 500 f/4L IS USM, or even $1000 for the often recommended Sigma 50-500 f/4-6.3 EX DG HSM. It won't achieve critical sharpness for high quality large prints, but can be plenty good enough for web posting or small prints (less than 8x12).
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Jon Close |
P.S. I found some discussions with samples from similar lenses: Kenko/Tokina 420-800 f/8.3-16 Opteka 650-1300 f/8-16 - long long discussion. One poster ordered the lens and sample photos appear beginning on pp. 15.
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Heather McCrory |
Very interesting, I really appriciate it. I have one more question. What do the teleconverters do? I guess if I were to get a 70-300mm, do they bring you in closer?...You have been a tremendous help. Again thanks
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Jon Close |
Teleconverters increase the lens focal length. The usual sizes are 1.4x and 2x. Because they increase the focal length, but cannot change the size of the lens diaphram opening (aperture), they also effective reduce the lens's aperture by 1 stop (1.4x) or 2 stops (2x). So a 70-300 f/4-5.6 lens with a 1.4x TC is effectively 98-420 f/5.6-8, and with a 2x TC is effectively 140-600 f/8-11. Most SLR autofocus systems require a maximum lens aperture of f/5.6 or wider to be effective. If a teleconverter makes the effective aperture smaller than that, then AF may be unreliable and hunt without ever confirming focus.
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Heather McCrory |
You have been so helpful. That is great stuff. Thanks again for taking the time to explain. Heather
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