Need help choosing a new zoom lens

[Discus]

Originally Posted by RobS

Agreed primes >>>>> zoom.

My favorit lens is my macro 105mm 2.8 Sigma EX. I don't know for Nikkon but in general the Sigma EX series gives very good value for money.

I used (and absolutely loved) this lens for years with a Canon film body (50E); when I upgraded to a EOS 5D, it didn't work properly, so I've also got a Canon 100mm Macro lens now. I really really like the images I got out of the Sigma. I'm not sure what's changed, but I don't like the macro shots coming out of my 5D as much. I suspect my camera technique has gotten a lot sloppier (handheld rather than tripod mounted), and I'm using total flash more... :/

With regards to the original question, yes, there does come a time when the consumer-level stuff is a bit limiting and you start looking at the high end & "pro-sumer" level stuff, and getting a bit sad at the prices.

My long lens is a 170-500mm Sigma, which is unreliable on the 5D (setting AP to wide open seems to help), but the camera often locks up. Annoying when shooting wildlife, and in general, a dreadfully slow, crappy lens.

I would dearly love a proper Canon 600mm F/4 IS, but then I could buy a car for that money. Which you'd need to cart the thing around

Primes are obviously and consistently better (at least when compared within a price bracket) than zooms - but sometimes the convenience of a zoom is handy. I usually leave my Canon 24-105mm L lens attached to the body. I rarely change to anything else unless I'm doing macro. I've hardly ever used my 16-35mm L lens.

If you want a really fast lens, the 50mm f1.4 is fantastic.

Generally, most people say that the "big brand" lenses are better than the after market guys. I would expect that would particularly apply to Nikon, who have quite the reputation as lens-makers (I once had the chance to look through the viewfinder of some BBC Wildlife cameraman's video/film camera with some fancy Nikon lens attached and was amazed by the clarity of the image. Of course, when your baseline is a Sigma 170-500...!).

I should probably see about getting the Sigmas re-chipped.

[Connie Star]

Originally Posted by Discus

I would dearly love a proper Canon 600mm F/4 IS, but then I could buy a car for that money. Which you'd need to cart the thing around

[RobS]

Originally Posted by Discus

Generally, most people say that the "big brand" lenses are better than the after market guys.

Probably they are but if you're talking value for money Sigma EX is great and most of us won't see the difference. Sure if you have the cash to spare and really like your fotography or are a perfectionist go for the high end big brand ones.

[tropterrarium]

Originally Posted by RobS

Probably they are but if you're talking value for money Sigma EX is great and most of us won't see the difference. Sure if you have the cash to spare and really like your fotography or are a perfectionist go for the high end big brand ones.

The "worst" thing you can do is to use a really good lens for a while, then go back. There is no going back, really. Once you realize what's possible, and how much one sacrifices with a mediocre lens, one only will be happy with the real thing. Renting a lens is a good way to find out before committing to a purchase.

re "most of us won't see the difference", a good lens cannot compensate for poor technique (bad focus, camera shake), but if the intention is to improve ones photography, then it is worthwhile to spend some time using proper technique and looking critically at images. Then you will see the differences also in terms of flare reduction, distortion, various aberrations, color rendition.

In this context, size also matters. If you only plan on showing the image on a phone, or printing it at 4x6 inches, probably one can get by with a compact camera. But once you blow it up a bit more, it really shows. Just printed a Masdevallia zahlbruckneri flower full-size at 13x19" last night, shot with a Zeiss Makroplanar ZE 100 mm f/2.0. Even the nicely rounded (not angular as in cheap lenses) out-of-focus areas (aka bokeh) are to die for.

Last but not least, what is the purpose of this new lens? Why is the old one not sufficient? These questions will be crucial to answer in order to find out what one needs/wants. It may even identify incompatible requirements; e.g., 18-500 mm zoom for hand-held low-light photography: either long range zoom with small f-stop (f/5.6) for sunny days or on tripod; or large f-stop (f/0.95-1.4) fix-focal, preferentially normal to wide angle.

As this is posted on OB, I assume that one important aspect is plant photography. This is in the close-up to true macro range. Zooms really perform poorly in that area; there are NO macro-zooms for a good reason. Some zooms have a special close-up setting. While it shows the object bigger, it also sacrifices enormously in quality. A zoom intended for flower photography is a non-starter.

Consider that lenses are optimal for one particular setting, deviate from that setting, and performance decreases, and the further one deviates from that setting, the worse it gets:
- one focal length: invariable with fix-focal, but is a factor with zooms.
- one focus distance/magnification. For regular lenses this is at infinity distance/magnification. For most macrolenses, this is at 1:5-1:10. Some specialized symmetrical lenses are optimized at 1:1. Please note, that this is the *optimum* magnification, not the maximum magnification (usually 1:2 or 1:1 with most macros).
- one f-stop. Usually 2-3 f-stops down from wide open.

For those interested, read Sidney Ray's Applied Photographic Optics. Even when skipping all the math, there is still plenty of good info in there.