I am considering buying a Sigma 2x EX DG APO Tele Converter to go with my 120mm-400mm Sigma zoom.
I know I will lose 2 stops and that Auto Focus won't work, but occasions when I need a lens between 600mm -800mm are rare and this is a hell of a lot cheaper option than a prime lens.
Does anyone have this combo or has anyone tried it?
Is it worth acquiring?
I have not tried that, but in general, putting a 2x on a lens like that will produce results that are generally unacceptable. You will likely lose a lot of sharpness. If I'm correct, your lens is f/5.6 at the 400 end? That means you'd be at f/11 with a 2x. I wouldn't bother.
Posted by Richard Ditch on June 21, 2013 at 11:28 AM
I'll second Keith on this. Zoom lenses are already optically challenged, especially at the long end. A 2x will drop overall image quality so much at the long end that you will just be wasting your time and money trying it. You'll likely get better results shooting without the 2x and cropping by 75%; yes, the noise will be quite prominent but you'll have a better chance of retaining some sharpness and detail.
If you still decide to use a 2x on that lens then make sure your field technique is up to it: sturdy tripod at all times; increase the ISO to counteract the drop in light; stop down 2-3 stops from wide open; pay close attention to critical focus; don't crop the result.
Posted by Martin Dunn on June 21, 2013 at 12:01 PM
Thanks Keith, Richard.
I suspected as much. I'll just pur the money in a jar and start saving for a longer lens.
Posted by David Graham on June 21, 2013 at 12:17 PM
To supplement Richard's "...if you must..." suggestions, I'd add that you try, at most, for an effective 600mm rather than 800mm. view. Drop your zoom back to 300mm which, with 2x TC will give you a 600mm view. The near and far extremes of any zoom aren't worth TC augmentation. But, if you drop back to maybe 60% to 75% of full zoom you may get some useable ( not optimal...just "useable") images.
Good luck,
Dave Graham
I used the Canon 2.0x TC (version II) on my 70-200mm/2.8 to get a 400mm/5.6 long landscape lens. I did several shoots with it.
I sold it.
At first glance images looked OK, until I started pixel-peeping with large prints in mind. That's when you realize that sending light through two sets of glass is a tricky business, and detail suffers. I had taken some Phoenix skyline images from across the valley while planted on the side of Camelback Mountain, and in hindsight I probably should have closed down two stop and piled sandbags on the lens to make sure it was absolutely rock steady. Ultimately I realized the Canon 400mm 5.6 lens was worth the price tag. However, if your output was strickly web-based galleries and you were never going to make the image bigger than 1200px, different story. Things that small hide artifacts, and you could get away with the TC. But chances are you've got prints in mind, and that's a tough one. Buy it from Amazon or some place it can be returned without hassle and try it out.
My experience is that a 2.0 teleconverter is acceptable with a fixed lens; most every photo I've posted here has been shot with a 2. teleconverter. But with zoom lenses the results are bad to awful.
As an example, using Olympus products, the 2.0 TC was perfectly acceptable on the 300mm; but on the 90-250mm f2.8, the photos were unusable, even though the 90-250mm is a prime lens.
Discussion
7 repliesI know I will lose 2 stops and that Auto Focus won't work, but occasions when I need a lens between 600mm -800mm are rare and this is a hell of a lot cheaper option than a prime lens.
Does anyone have this combo or has anyone tried it?
Is it worth acquiring?
If you still decide to use a 2x on that lens then make sure your field technique is up to it: sturdy tripod at all times; increase the ISO to counteract the drop in light; stop down 2-3 stops from wide open; pay close attention to critical focus; don't crop the result.
I suspected as much. I'll just pur the money in a jar and start saving for a longer lens.
Good luck,
Dave Graham
I sold it.
At first glance images looked OK, until I started pixel-peeping with large prints in mind. That's when you realize that sending light through two sets of glass is a tricky business, and detail suffers. I had taken some Phoenix skyline images from across the valley while planted on the side of Camelback Mountain, and in hindsight I probably should have closed down two stop and piled sandbags on the lens to make sure it was absolutely rock steady. Ultimately I realized the Canon 400mm 5.6 lens was worth the price tag. However, if your output was strickly web-based galleries and you were never going to make the image bigger than 1200px, different story. Things that small hide artifacts, and you could get away with the TC. But chances are you've got prints in mind, and that's a tough one. Buy it from Amazon or some place it can be returned without hassle and try it out.
As an example, using Olympus products, the 2.0 TC was perfectly acceptable on the 300mm; but on the 90-250mm f2.8, the photos were unusable, even though the 90-250mm is a prime lens.
Save your nickels. It will be worth it.