All Forum Comments
Comment by CraigF1969 posted on F.O.A. Scottthehat; Focus tests as requested. at 23/05/2009 - 09:04
Mannesty wrote:
The last shots look "woeful" because it appears you have a quite bad front focussing issue. You will not see this in an image of a flat subject that is parallel with the sensor's focal plane. It's obvious in the shots of the chart though.
Yes, any adjustment for focus issues at one end of the zoom range might adversely affect focussing at the other end. I think we have to live with that.
Primes are the only real answer to this problem, or very expensive zooms manufactured to tighter designs and tolerences.
The tests were all just done @ the 400mm for the time being.The last shots look "woeful" because it appears you have a quite bad front focussing issue. You will not see this in an image of a flat subject that is parallel with the sensor's focal plane. It's obvious in the shots of the chart though.
Yes, any adjustment for focus issues at one end of the zoom range might adversely affect focussing at the other end. I think we have to live with that.
Primes are the only real answer to this problem, or very expensive zooms manufactured to tighter designs and tolerences.
The comment you made Mannesty above is not entirely true as Sigma have fixed this on lots of occasions for others and when i spoke to them last week about the focus speed also they commented they had resolved that issue and thats when they tried to lay the fault with the camera.
On that occasion they could have been correct as the camera had a fault and was returned.
I will try the focus adjustment and see if there is a marked improvement.
Comment by CraigF1969 posted on F.O.A. Scottthehat; Focus tests as requested. at 23/05/2009 - 09:02
Just did the focus test as they said on the blog.
Flat table, tripod, AF, focus on the cross.
Heres the crops.
These look woefull at all apertures.
f5.6
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus256-1.jpg[/IMG]
f6.3
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus263-1.jpg[/IMG]
f7.1
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus271-1.jpg[/IMG]
f8
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus280-1.jpg[/IMG]
f9
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus290-1.jpg[/IMG]
Flat table, tripod, AF, focus on the cross.
Heres the crops.
These look woefull at all apertures.
f5.6
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus256-1.jpg[/IMG]
f6.3
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus263-1.jpg[/IMG]
f7.1
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus271-1.jpg[/IMG]
f8
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus280-1.jpg[/IMG]
f9
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus290-1.jpg[/IMG]
Comment by CraigF1969 posted on F.O.A. Scottthehat; Focus tests as requested. at 23/05/2009 - 00:11
scottthehat wrote:
have you tried adjust the front focus, also how did you do the focus chart test as to me i looks like it has major front focus,
I havent tried the focus adjuster as according to reports if you adjust for front or back focus @ 400mm you get major front or back at the 120-250mm range.have you tried adjust the front focus, also how did you do the focus chart test as to me i looks like it has major front focus,
Comment by CraigF1969 posted on F.O.A. Scottthehat; Focus tests as requested. at 23/05/2009 - 00:00
Here they are.
No PP, all the same ISO.
Tripod Mounted.
2 second timer.
SR OFF.
F5.6
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus256.jpg[/IMG]
F6.3
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus263.jpg[/IMG]
F7.1
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus271.jpg[/IMG]
F8
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus280.jpg[/IMG]
F9
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus290.jpg[/IMG]
F5.6
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus56.jpg[/IMG]
F6.3
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus63.jpg[/IMG]
F7.1
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus71.jpg[/IMG]
F8
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus80.jpg[/IMG]
F9
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus90.jpg[/IMG]
No PP, all the same ISO.
Tripod Mounted.
2 second timer.
SR OFF.
F5.6
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus256.jpg[/IMG]
F6.3
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus263.jpg[/IMG]
F7.1
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus271.jpg[/IMG]
F8
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus280.jpg[/IMG]
F9
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus290.jpg[/IMG]
F5.6
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus56.jpg[/IMG]
F6.3
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus63.jpg[/IMG]
F7.1
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus71.jpg[/IMG]
F8
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus80.jpg[/IMG]
F9
[IMG]http://i271.photobucket.com/albums/jj132/CraigF1969/private/focus90.jpg[/IMG]
Comment by CraigF1969 posted on F.O.A. Scottthehat; Focus tests as requested. at 22/05/2009 - 23:36
All done..
Will create a new thread titled FOA Scottthehat
Will create a new thread titled FOA Scottthehat
Comment by CraigF1969 posted on Some 400mm Tests at 22/05/2009 - 23:31
scottthehat wrote:
well try some shots on a cereal box using a steady surface, and show the original and a crop of a section the same on each. using the same iso and shutter speed,
Will do that just now. Tripod is already set up in the kitchen for the birdies earlier. well try some shots on a cereal box using a steady surface, and show the original and a crop of a section the same on each. using the same iso and shutter speed,
Comment by CraigF1969 posted on Some 400mm Tests at 22/05/2009 - 22:57
scottthehat wrote:
i would take it back to srs quick, and ask to test another one, personaly i think it looks abit sotf to me and i found my 150-500mm hsm not as fast focusing as both my 170-500mm sigmas, i found that i needed to use f10 min on my 150-500mm at 500mm and both my 170-500mm were and are sharper at f6.3 at 500mm,
Not possible to take it back and test against another as i live in Lanarkshire in Scotland and bought it online.i would take it back to srs quick, and ask to test another one, personaly i think it looks abit sotf to me and i found my 150-500mm hsm not as fast focusing as both my 170-500mm sigmas, i found that i needed to use f10 min on my 150-500mm at 500mm and both my 170-500mm were and are sharper at f6.3 at 500mm,
Guess my only options are to either accept it or contact Sigma and see what they have to say although i spoke to them last week about how fast it should focus and they couldnt give me an answer.
I also metioned i thought it was really soft at f5.6 and they basically said that it was the cameras fault.
I just did some googling on the focus speed and it seems loads of people have returned these due to them having really bad focus speeds.
Comment by CraigF1969 posted on Some 400mm Tests at 22/05/2009 - 22:47
Greytop wrote:
Looks good to me Craig, what do you think about the sharpness?
If im being honest i was expecting the f8.0 result to be the f5.6. Looks good to me Craig, what do you think about the sharpness?
f8 seems to be the minimum useable aperture which is not really great.
Comment by CraigF1969 posted on Some 400mm Tests at 22/05/2009 - 21:35
Bought the lens new just over a week ago from SRS.
Im still getting times of over 2 to 3 seconds focusing from infinity to target and thats on a stand out object with nothing in the background.
Im still getting times of over 2 to 3 seconds focusing from infinity to target and thats on a stand out object with nothing in the background.
Comment by CraigF1969 posted on Some 400mm Tests at 22/05/2009 - 21:33
Many modern zooms are not zooms at all but varifocals. They do not hold their focus when zoomed. Very expensive ones do, very cheap ones definitely don't, but there's a whole grey area between those two extremes where some hold focus better than others.
Try it. Manually focus very precisely on something and then zoom in and see if it doesn't blur instantly.