Lens advice..

FeatherMonkey · Jun 15, 2015

Have a Canon 600d, presently own
Sigma 105mm f2.8 macro
Sigma 18-250mm f3.5-6.3
Canon 50mm f1.8

Have to be honest tend to find I default to the Sigma 105mm just think the image quality is a little brighter. The problem is I'm finding it quite constricting due to crop format. The other Sigma I've never quite been happy with, do wonder whether I've just not spent enough time using it. The 50 is what it is, whilst nice I just tend to choose the 105mm.

So I've seen a
Canon 17-40mm f4 L
Sigma 15-30 f3.5-4.5

The first problem whilst I have an overlap with Sigma 18-250mm, am I just seeing the limits of superzooms? The other will I see a difference with one of the above?

Just pros for 1 and the other, the Canon I guess will give me a better IQ, but Sigma gives me crop wide(yet not sure, guess this is as wide as possible without a fisheye).

Just curious should I invest in 1 of the above or is it me just not quite getting the superzoom to work and practice more ?

TCampbell · Jun 15, 2015

The advantage of a superzoom is the convenience factor. When you use a lens with a less ambitious zoom range, you'll tend to get better results. The "kit" lens for APS-C crop-factor cameras tends to be an 18-55mm zoom -- mostly because that offers a little wide angle and a little (not much) telephoto with respectable optical quality.

A "normal" focal length for your camera is close to 28mm. Anything longer will seem "telephoto" (even if only fractionally) and anything shorter will seem "wide angle".

Canon's high-end lens in the category is the EF-S 17-55mm f/2.8 IS USM (it can provide f/2.8 at all focal lengths). Canon does make two different ultra-wide zooms... an EF-S 10-22mm f/3.5-4.5 and they just introduced a new EF-S 10-18mm f/4.5-5.6 IS STM lens. These are both "rectilinear" (no fish-eye distortion) wide angle lenses.

The EF 17-40mm f/4L can be used on a full-frame body since it's an EF lens ... not EF-S. Unless you plan on buying a full-frame body in the possibly near future, I'd probably prefer the EF-S 17-55mm f/2.8 IS USM over the EF 17-40mm f/4L USM.

FeatherMonkey · Jun 16, 2015

Thanks for that, guess I'm going to have to make a decision sooner rather than later in regards to ff vs crop.

At the moment apart from the zoom the other 2 are ff. Yet I'm not that invested yet in either size or system.

Was I to stay with Canon crop I guess the 7dii would be the aim. What would be my next crop body step be? Also what would the Nikon equivalents be?

Also take it the Sigma 15-30 isn't really bringing much to the table then? Also from a crop format am I right generally to get the better lenses I am going to have to invest in ff lenses, with the compromises and extra glass?

Dao · Jun 16, 2015

For lens purchase, I'll recommend look at the focal length first. Find out the focal length or range you want. You can do so with your super zoom lens. The key is the field of view. If you believe you like to get a better lens to cover a particular focal length, then look for corresponding lenses. Once you have few choices, compare them with the help of online lens review site including technical as well as user reviews.

Here are some sites that may help.
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