A900 + Sigma 70-300 APO + SONY 70-300G + Minolta 100-400 APO

TME · 19th March 2009

Hello had some more tests on 3 telephoto zooms that I own...

Just a handheld shot first of all... SONY 70-300G, ISO800, f/8.0, no flash, centre AF focus sensor, specific focus area is the right eye of the pink bear.

At 100%, not as sharp as I have seen, likely due to camera shake... I did not switch on SSS... forgot to switch it back on after mounting on tripod...

Centre Crop f/8.0

TME · 19th March 2009

Sigma 70-300 APO

I noticed a very strange phenomenon... the vignetting wide open at the wide end is rather bad... this is a full frame lens, so it's a bit surprising... it's bad enough to notice in the viewfinder... the vignetting clears up only at f/8

Centre AF sensor, Focus is on the first Chinese character in the centre of the frame. AF was done zoomed in at 300mm, to ensure that the first Chinese character rested inside the centre AF square and then zoomed out and focused... interestingly, focus confirm at 300mm and then again at 700 when zoomed out was different... you could hear the lens shift... not sure if this would cause any focusing errors at 70mm or not...

70mm, tripod, f/4 + 100% crop

70mm, tripod, f/5.6 + 100% crop

TME · 19th March 2009

70mm, tripod, f/8 + 100% crop

70mm, tripod, f/16 + 100% crop

TME · 19th March 2009

70mm, tripod, f/22

TME · 19th March 2009

Sigma 70-300 APO

The absurd thing is that vignetting is worse at 135mm... ???

Centre AF sensor, Focus is on the first Chinese character in the centre of the frame. AF was done zoomed in at 300mm, to ensure that the first Chinese character rested inside the centre AF square and then zoomed out and focused... interestingly, focus confirm at 300mm and then again at 135mm when zoomed out was the same...

135mm, tripod, f/4.5 + 100% crop

135mm, tripod, f/5.6 + 100% crop

TME · 19th March 2009

135mm, tripod, f/8 + 100% crop

135mm, tripod, f/16 + 100% crop

TME · 19th March 2009

135mm, tripod, f/22 + 100% crop

TME · 19th March 2009

Sigma 70-300 APO

Vignetting is very heavily pronounced at 300mm: Notice that the image at f/22 is much brighter than at f/5.6?!!! The shadow over the entire image is quite obvious at f/5.6 and f/8 such that the image is darkened... I really have no idea why... but at f/16 and at f/22 it is much brighter... in fact f/22 is brightest...

Here the difficulty was also camera shake... the viewfinder is so big and bright you could see the image in the viewfinder moving up and down as you press the shutter to release the 10sec timer... as the oscillations come to a stop, a gust of wind picks it up again... very annoying... not as sharp as it could be I would say...

Centre AF sensor, Focus is on the first Chinese character in the centre of the frame.

300mm, tripod, f/5.6 + 100% crop

300mm, tripod, f/8 + 100% crop

TME · 19th March 2009

300mm, tripod, f/16 + 100% crop

300mm, tripod, f/22 + 100% crop

TME · 19th March 2009

In conclusion:

1) The Sigma 70-300mm APO can be pretty sharp... I'll repost in this thread a sharp example when I can get a windless day shot of something...

2) Resolution is pretty ok even on a 24MP sensor... it's quite clear that the sensor outresolves the lens (look at the fine detail) but do also note that camera shake comes into play...

3) For some reason there was significant vignetting at wider apertures. This seems strange as it usually does not occur for telephoto zooms? Maybe someone can enlighten me here...

TME · 19th March 2009

SONY 70-300 G

The same vignetting issue is seen for the SONY G lens. The coating on the lens is also quite different - for the same aperture and focal length, the SONY images looks darker. The reason is that the tint imparted by the lens is different. The Sigma imparts a greenish tint which increases the luminance (green channel) whereas the SONY lens imparts a reddish tint, much warmer. And this also tends to contribute to more noise and loss of detail, this much I have noticed...

If you compare the 70mm shots at f/5.6, it is quite apparent that the Sigma shot has significant barrel distortion whereas the SONY shot is free of this distortion... it's only when you switch between images that this becomes apparent.

It's also quite apparent that the sharpest apertures are f/8 - 16. In fact at f/16 there is slight diffraction softening and it's very apparent at f/22.

Centre AF sensor, Focus is on the first Chinese character in the centre of the frame. AF was done zoomed in at 300mm, to ensure that the first Chinese character rested inside the centre AF square and then zoomed out and focused... interestingly, focus confirm at 300mm and then again at 700 when zoomed out was different... you could hear the lens shift... not sure if this would cause any focusing errors at 70mm or not...

70mm, tripod, f/4.5 + 100% crop

70mm, tripod, f/5.6 + 100% crop

TME · 19th March 2009

70mm, tripod, f/8 + 100% crop

70mm, tripod, f/16 + 100% crop

TME · 19th March 2009

70mm, tripod, f/22 + 100% crop

TME · 19th March 2009

SONY 70-300 G

Significant improvement in vignetting at 135mm... only slight vignetting at f/5.6. However significant darkening occurs from f/16 onwards... There is also considerable improvement in sharpness at all aperture values...

Centre AF sensor, Focus is on the first Chinese character in the centre of the frame. AF was done zoomed in at 300mm, to ensure that the first Chinese character rested inside the centre AF square and then zoomed out and focused... interestingly, focus confirm at 300mm and then again at 135mm when zoomed out was the same...

135mm, tripod, f/5.6 + 100% crop

135mm, tripod, f/8 + 100% crop

TME · 19th March 2009

135mm, tripod, f/16 + 100% crop

135mm, tripod, f/22 + 100% crop

TME · 19th March 2009

SONY 70-300 G

For an unstabilised tripod, this is really sharp... 300mm is where this lens seems to excel although it was a lready very sharp at 135mm... extremely well-resolved details...

Centre AF sensor, Focus is on the first Chinese character in the centre of the frame. AF was done zoomed in at 300mm, to ensure that the first Chinese character rested inside the centre AF square and then zoomed out and focused... interestingly, focus confirm at 300mm and then again at 700 when zoomed out was different... you could hear the lens shift... not sure if this would cause any focusing errors at 70mm or not...

300mm, tripod, f/5.6 + 100% crop

300mm, tripod, f/8 + 100% crop

TME · 19th March 2009

300mm, tripod, f/16 + 100% crop

300mm, tripod, f/22 + 100% crop

TME · 19th March 2009

Minolta 100-400 APO

An old venerable lens... image quality was superb on the film 7 and the 7D... it's slow of course cos the whole lens barrel turns as the lens focuses... but it has good reach at an affordable price and very good quality... oh and 400mm without a tripod isn't quite useful handheld... you've really got to be rock steady, practise excellent breathing technique, get some support, and use the continuous drive mode...

One issue with this lens is that it's very long and heavy even at 100mm and without a tripod collar, it always droops even on a Manfrotto 190B and a huge 488RCO ballhead... and it's tough to keep it still handheld or even on tripod... it tend to sway even in a light breeze...

Vignetting is the order of the day but diminshes by f/8 and only disappears at f/16...

Centre AF sensor, Focus is on the first Chinese character in the centre of the frame. AF was done zoomed in at 400mm, to ensure that the first Chinese character rested inside the centre AF square and then zoomed out and focused... interestingly, focus confirm at all focal lengths was the same.

100mm, tripod, f/4.5 + 100% crop

100mm, tripod, f/5.6 + 100% crop

TME · 19th March 2009

100mm, tripod, f/8 + 100% crop

100mm, tripod, f/16 + 100% crop

TME · 19th March 2009

100mm, tripod, f/22 + 100% crop

19th March 2009	#1
TME Senior Member Join Date: Jan 2002 Location: Clementi Posts: 6,188	A900 + Sigma 70-300 APO + SONY 70-300G + Minolta 100-400 APO Hello had some more tests on 3 telephoto zooms that I own... Just a handheld shot first of all... SONY 70-300G, ISO800, f/8.0, no flash, centre AF focus sensor, specific focus area is the right eye of the pink bear. At 100%, not as sharp as I have seen, likely due to camera shake... I did not switch on SSS... forgot to switch it back on after mounting on tripod... Centre Crop f/8.0 Last edited by TME; 19th March 2009 at 09:17 PM.

19th March 2009	#2
TME Senior Member Join Date: Jan 2002 Location: Clementi Posts: 6,188	Re: A900 + Sigma 70-300 APO + SONY 70-300G + Minolta 100-400 APO Sigma 70-300 APO I noticed a very strange phenomenon... the vignetting wide open at the wide end is rather bad... this is a full frame lens, so it's a bit surprising... it's bad enough to notice in the viewfinder... the vignetting clears up only at f/8 Centre AF sensor, Focus is on the first Chinese character in the centre of the frame. AF was done zoomed in at 300mm, to ensure that the first Chinese character rested inside the centre AF square and then zoomed out and focused... interestingly, focus confirm at 300mm and then again at 700 when zoomed out was different... you could hear the lens shift... not sure if this would cause any focusing errors at 70mm or not... 70mm, tripod, f/4 + 100% crop 70mm, tripod, f/5.6 + 100% crop Last edited by TME; 19th March 2009 at 09:33 PM.

19th March 2009	#3
TME Senior Member Join Date: Jan 2002 Location: Clementi Posts: 6,188	Re: A900 + Sigma 70-300 APO + SONY 70-300G + Minolta 100-400 APO 70mm, tripod, f/8 + 100% crop 70mm, tripod, f/16 + 100% crop Last edited by TME; 19th March 2009 at 09:33 PM.

19th March 2009	#4
TME Senior Member Join Date: Jan 2002 Location: Clementi Posts: 6,188	Re: A900 + Sigma 70-300 APO + SONY 70-300G + Minolta 100-400 APO 70mm, tripod, f/22

19th March 2009	#5
TME Senior Member Join Date: Jan 2002 Location: Clementi Posts: 6,188	Re: A900 + Sigma 70-300 APO + SONY 70-300G + Minolta 100-400 APO Sigma 70-300 APO The absurd thing is that vignetting is worse at 135mm... ??? Centre AF sensor, Focus is on the first Chinese character in the centre of the frame. AF was done zoomed in at 300mm, to ensure that the first Chinese character rested inside the centre AF square and then zoomed out and focused... interestingly, focus confirm at 300mm and then again at 135mm when zoomed out was the same... 135mm, tripod, f/4.5 + 100% crop 135mm, tripod, f/5.6 + 100% crop Last edited by TME; 19th March 2009 at 09:39 PM.