Sigma 300mm f2.8 - any experiences?
Discussion
V6GTO said:
Have you felt the weight of one?
It's not that heavy Martin....well compared to your feather light 100-400IS I guess it's a bit weighty
I got the 2X Sigma converter with my 120-300. Autofocus is fine with a 1D MkII. It'll try it on a 10D if you like but as it's still F5.6 I'm ure it'll be fine.
The real issue is 600mm is rather tricky to use. I look at it this way. My big telescope is only 500mm (without barlow lenses etc). With that and it's massive stand on my deck, I can see the vibrations from my heartbeat through the deck!
ThatPhilBrettGuy said:
I got the 2X Sigma converter with my 120-300. Autofocus is fine with a 1D MkII. It'll try it on a 10D if you like but as it's still F5.6 I'm ure it'll be fine.
The real issue is 600mm is rather tricky to use. I look at it this way. My big telescope is only 500mm (without barlow lenses etc). With that and it's massive stand on my deck, I can see the vibrations from my heartbeat through the deck!
That's interesting feedback (all of you, but specifically TPBG) because the kit in question (not mine) involves a 1D Mk2. (At least I think it is a Mk 2)
From the sample test shots I have seen it looks like the auto focus is setting up just ahead of the prime subject target point. Given that the main use or bird photography, so distances to subject are usually as short as possible to fill the frame, the DoF is very narrow and anything other than spot-on accuracy will tend to produce a largely unsharp image. Things improve, as you might expect, as the lens is stopped down - but not by much. It also seems to have a problem with bright yellow colours next to red.
The target subject for the test shots is a large soft toy, mostly bright red in the main target area. Could that be a problem? (The birds in the garden could not be persuaded to pose for half an hour while the tests were run ...)
Is it the Sigma 2X they're using? To be honest it's not the best teleconverter in the world. The lens itself should be fine without. I did get a duff one at first but it was swapped out straight away, no questions. My first lens was soft on one side.
I can't think why certain colours would be an issue. Try the old photo of a leafless tree against a grey sky to see if there's some other nasty optical things going on.
As for focus issues, well mine is spot on, but as you say the DOF is, er, minimal at best wide open and it doesn't take much to get the camera looking elsewhere. Also remember that the focusing happens with the lens wide open anyway, so manually stopping it down doesn't make any odds.
If you need any test shots taking, no problem, although they'll be of little use if it's a 300mm and not a 120-300mm. With and without teleconverter may tell a story though.
I can't think why certain colours would be an issue. Try the old photo of a leafless tree against a grey sky to see if there's some other nasty optical things going on.
As for focus issues, well mine is spot on, but as you say the DOF is, er, minimal at best wide open and it doesn't take much to get the camera looking elsewhere. Also remember that the focusing happens with the lens wide open anyway, so manually stopping it down doesn't make any odds.
If you need any test shots taking, no problem, although they'll be of little use if it's a 300mm and not a 120-300mm. With and without teleconverter may tell a story though.
ThatPhilBrettGuy said:
Is it the Sigma 2X they're using? To be honest it's not the best teleconverter in the world. The lens itself should be fine without. I did get a duff one at first but it was swapped out straight away, no questions. My first lens was soft on one side.
Not absolutely sure but I think it is a Sigma convertor. When it's right it produces what seem to be very good shots to my eyes. But may lack onsistency for some reason.
ThatPhilBrettGuy said:
I can't think why certain colours would be an issue. Try the old photo of a leafless tree against a grey sky to see if there's some other nasty optical things going on.
Nor can I unless the measurement system is affected by a certain light spectrum and it dominated.
ThatPhilBrettGuy said:
As for focus issues, well mine is spot on, but as you say the DOF is, er, minimal at best wide open and it doesn't take much to get the camera looking elsewhere. Also remember that the focusing happens with the lens wide open anyway, so manually stopping it down doesn't make any odds.
Yep, the DoF can be seen 'improving' as the settings dictate a change in f. Just difficult (on the shots I have seen) to work out exactly where it is setting the focus.
ThatPhilBrettGuy said:
If you need any test shots taking, no problem, although they'll be of little use if it's a 300mm and not a 120-300mm. With and without teleconverter may tell a story though.
Thanks for the offer but I think this may be a combination specific thing it there is any sort of (slight) problem. Slight in overall terms but significant for the use intended of course.
I have seen samples with and without convertor and they look much the same other than the difference in perspective. In fact I was quite impressed but the convertor performance! The DoF almost disappears of course at minimum focus distance.
I have suggested some different test shots which should put the Canon version of spot metering under some pressure if they are performed.
The thing is he previously used a 600mm Canon manual focus lens with EOS mount adaptor so any focus issues were down to the user. I guess that is easier to live with than having the machine appear to get it wrong.
As I have never had an AF lens on an SLR I don't know. ( I have enjoyed the manual Canon 600mm f4.5 so far though! ;-) Looking for a suitable dedicated fitness class to get into shape for using it ASAP! Weight training anyone?)
Thanks for all your input to this.
Update:
Having run some tests ...
The requirement is bird photos so working with a very narrow DoF - about 2 cms at typical 'fill the frame' shooting distances.
The lens performs pretty well - 'spot on' was the comment made.
Fit the 2x convertor and the focus point seems to move to about 1cm in FRONT of the target point - which is a bit of a problem with a 2cm DoF.
Other than simpo's wide angle experience recently has anyone else come across anything which may be similar? Admittedly if you were not shooting small subjects at relatively long distances you might not notice. Unless the effect is proportionate to distance I don't think I would spot a 1cm error on focusing from about 50 metres for cars approaching, say, the Melbourne Hairpin at Donington. Funny how things can be soooo critical or not according to the application to which they are being put.
Observations anyone?
Having run some tests ...
The requirement is bird photos so working with a very narrow DoF - about 2 cms at typical 'fill the frame' shooting distances.
The lens performs pretty well - 'spot on' was the comment made.
Fit the 2x convertor and the focus point seems to move to about 1cm in FRONT of the target point - which is a bit of a problem with a 2cm DoF.
Other than simpo's wide angle experience recently has anyone else come across anything which may be similar? Admittedly if you were not shooting small subjects at relatively long distances you might not notice. Unless the effect is proportionate to distance I don't think I would spot a 1cm error on focusing from about 50 metres for cars approaching, say, the Melbourne Hairpin at Donington. Funny how things can be soooo critical or not according to the application to which they are being put.
Observations anyone?
I'd suggest it's a percentage error rather than a fixed distance error.
With my myopic Sigma 20-40mm's the effect was much less obvious at medium/long range than close range, so I think the sternest test might be to try the minimum focusing distance. Photograph a newspaper at 45 degrees. If the line you aimed at isn't sharp, but one of the other lines is, be afraid
>> Edited by simpo two on Friday 3rd February 21:54
With my myopic Sigma 20-40mm's the effect was much less obvious at medium/long range than close range, so I think the sternest test might be to try the minimum focusing distance. Photograph a newspaper at 45 degrees. If the line you aimed at isn't sharp, but one of the other lines is, be afraid
>> Edited by simpo two on Friday 3rd February 21:54
simpo two said:
I'd suggest it's a percentage error rather than a fixed distance error.
With my myopic Sigma 20-40mm's the effect was much less obvious at medium/long range than close range, so I think the sternest test might be to try the minimum focusing distance. Photograph a newspaper at 45 degrees. If the line you aimed at isn't sharp, but one of the other lines is, be afraid
I'm told it was at the minimum distance - 11ft for the lens alone, 12ft for the lens with convertor. I have seen the test shots - not quite as you described but pretty similar in effect using the Canon's spot focus feature. The results bear out the claims as far as I can tell.
He knows that people are using the long Sigma lens (and its relatives) with and without the convertor very successfully for the same subject matter so wonders if there is some sort of 'fix' available or whether this is just a slightly less accurate convertor. Either way it's annoying for him given his preferred subject matter.
Ain't technology fun!
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