Sigma 120-300mm f/2.8 OS for BIF?

OK, the OS version of this lens has been out for a while now. I've seen lots of excellent images of perched birds taken with this optic, but very few BIF. Compared to the Canon 500/4, the price remains very appealing - even with a Canon 2X III attached. Does anyone out there have any experience with this lens and BIF? I know it doesn't have a focus limiter and I'm concerned about the AF acquisition speed. I'd probably rent one before I seriously consider buying it, but would still be interested in the experience of others.

I bought one with Sigma's TC 2X. I also have a Kenko TC 1.4X. I haven't used the 120-300 much. I think a monopod is a must. For BIF a tripod with a gimbal head would be a lot better.
I'll try to perform the microfocus ajustment next weekend.

I would say that focus locks quick ( not as quick as Canon's USM) if the focus point is already on a subject with enough contrast. If not it will hunt all the way and sometimes doesn't lock at all. I used it only with a 7D and 1 AF-point selected.

Let me know if there are any tests that you would like me to perform.

My 0.02.;)

Thanks, Fabio. I'm not in a hurry, but will be very interested to see what you get in the way of BIF. I have a tripod/gimbal, so that's not an issue.

Happy New Year.

Quote:

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Originally Posted by fabiobernardino

Let me know if there are any tests that you would like me to perform.

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Fabio,

I would be interested in seeing an image of the moon, posted at 100% (an 800x1000 original pixel crop) at full zoom (300 mm). The moon is a tough subject with it's high contrast and fine detail.

Roger

Roger, any guidelines ?

I have a Canon 50D and 7D. I read somewhere that the 7D has 2 patterns of green in the CFA. Would it make a difference ?

Setup ?
- tripod
- cable release
- mirror lockup
- focus
- auto-focus or
- manual focus with live view (using 10x magnification) ?
- any suggested aperture, shutter, ISO ?
- Image format. I shoot RAW. Should I use jpeg with default picture style ? If RAW, let me know the recommended settings. I use Lightroom.

Let me know.

Quote:

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Originally Posted by fabiobernardino

Roger, any guidelines ?

I have a Canon 50D and 7D. I read somewhere that the 7D has 2 patterns of green in the CFA. Would it make a difference ?

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Hi Fabio,
No, the 7D will do very well. Figure 2 here: http://www.clarkvision.com/articles/telephoto_reach/
shows a 7D image of the moon with a 300 mm lens.

Quote:

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Originally Posted by fabiobernardino

Setup ?
- tripod
- cable release
- mirror lockup
- focus
- auto-focus or
- manual focus with live view (using 10x magnification) ?
- any suggested aperture, shutter, ISO ?
- Image format. I shoot RAW. Should I use jpeg with default picture style ? If RAW, let me know the recommended settings. I use Lightroom.

Let me know.

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ISO 100 or 200, wide open, tripod, mirror lockup, cable release or 2-second delay if using the shutter button. Try both focus methods and see which works best.
The moon should be very high in the sky.

Roger

I too am very interested in any BIF reports on this lens. I have seen some stunningly sharp perched bird images on POTN and some other forums but nothing in the way of BIF, and am also concerned with the lack of focus limiter.