Experimenting ... (1 Viewer)

I was playing around with my Sigma 170-500 zoom, a Canon 2x teleconverter and a 1D mkII at the lakeside and was not too thrilled with the results, viz the part of the original RAW image converted to jpg with fairly standard settings attached to this post. As far as I'm aware, the lens in question is not strictly compatible with the teleconverter, and even from what I was seeing in the viewfinder I got the impression the optics were not as sharp/contrasty as they might have been. This is just one of quite a few images with different f stops, ISO etc., and I don't think there was any substantial problem with camera shake or the (hand) focussing and the subject was just floating about slowly in fairly good light. Anyway, my question is, is this about the best one could expect to do with this kind of set up or would the results be significantly better with a "compatible" telephoto lens, e.g. one of the big Canons? Or is it just another case of a bad workman etc. - I've "only" been trying to snap birds for about a year now, mostly with fairly modest equipment, so I'm not particularly averse to criticism. Oh, and please excuse me if this has all been gone over before in great detail elsewhere ...

M.

Hi Momo

Considering your equipment the results look pretty good. However if you want improved definition I would upgrade that 170-500 to something better. You should be looking at Canon L lens. This will entail extra expense and open the debate of the benefits of zoom and prime lens. Most people stick with a x1.4 TC as opposed to a x2 TC because of the loss of quaility. The TC only really works well with top end primes lens. The poorer the lens quaility the worst the results are with a TC. I did see an article that showed that photoshop resampling just the Canon L lens gave better results than Canon L lens with a x2 TC.

A link that compares Lens Quaility

http://www.photozone.de/active/survey/querylens.jsp

As you will see that the 170-500 is OK but there are better lens out there.

A few folks on the forum have upgraded from the Sigma 170-500 to Sigma 500 and are very pleased with the results. This lens is expensive but not as expensive as the Canon 500.

Robert

Thanks for the comments, which rather confirm what I thought. I've taken the original image out of my gallery and replaced it with this , taken without the converter from a little less far away.

Yes that is an improvement - when I was doing research on what TC to get it would appear most folk were happy with a good prime and a x1.4TC. Most were unhappy with the x2TC combo especially if used with a zoom.

Robert

I'd agree with Robert on this - it's an issue of the lens not being the best and the 2x tc picking up the problems.

I used the Sigma 170-500 for a while and although it is a good lens it does not deliver the sharp detail that expensive prime lenses do. In the end I upgraded to the Sigma 500 f4.5, I have been very pleased with the results this lens gives, remains sharp even with a 1.4x tc.

Just as a sort of post scriptum, here is pretty much the same duck in the same place at the same time of day nearly a year on, this time with a Canon 100-400 zoom and a 1.4 x convertor. Whilst it's not that great with the zoom unless the lighting is particularly good, I tend to leave the convertor on to stop dust getting on the sensor (and I hate cleaning the sensor). I'm not sure it's all down to the lens, but I know which image I prefer.

M.

And finally, here is the same duck on a different day, about 5 cm from where it was two days before, taken with a different lens. Hardly birdwatching at its most thrilling but it makes for an interesting comparison. At least somebody somewhere might find it interesting. Oh well, I'm off to do something more useful like weed the living room or water the cat.

The170-500mm sigma lens will certainly provide good sharp images in good light (provided you have a good steady support) but is too slow to be used in conjuction with any convertor that I have ever tried. For the money this lens will deliver, you just have to be aware of its limitations. A converter is just not workable with this lens.