I just got the new Sigma 150-500mm and kind of find it soft. So am wondering if the distance I have been testing it with has anything to do with that.
I have been taking shots from 100-300 yrds. Is it possible that the farther away the subject the more prone to softness? I also had the in camera sharpening to off. I'm using the D200 and even with a SS of 800-1250 and ISO between 400-1250 at those distances soft is what I get. Will do some more tests at SS priority.
This shot is uncropped at 500mm, ISO 100, SS 200, f/7.1 hand held
Thoughts on this please.
Posted by Steve Foss on August 14, 2008 at 2:38 PM
Andre, I haven't shot that lens, so these are thoughts about telephoto zoom performance and testing in general.
At distances like that, the atmosphere can cause some softness. Humid days put texture in the air that softens distant shots. To do a better test for sharpness, mount the lens on a solid tripod and use a remote shutter release or the camera's self timer after focusing. Even with IS, camera shake while handheld can come into play as another cause of softness, and the tripod test will remove that possibility. I generally focus on a subject fairly close, a few feet beyond the lens MFD, so I have a lot of detail to pixel peep on. I like using a propped-up magazine, propping it so the bottom is closer and the top slants away somewhat. The contrast on the mag cover (or white inside pages) gives the autofocus something to grab onto easily, and reading words in an image is a very good test of sharpness.
All that being said, zooms are inherently softer than primes, in my experience, and stopping a lens down one stop usually produces a noticeable increase in sharpness.
And that being said, it's also just possible that model of lens is a bit soft, or that you have a soft copy and may need to exchange it.
But the tripod test usually separates the sheep from the goats. I like to use a subject that has some depth to ensure you'll be able to see the very sharpest portion of the DOF and make your judgment based on that. I don't like tests using flat subjects (exactly parallel to the sensor plane) because they can look a little soft if the camera is back- or front-focusing the lens a bit. If that happens, the test does not accurately gauge the inherent sharpness of the lens.
I'm also curious about what you're comparing it to when you say it is soft. Another lens? Your mind's eye and your own impression of what sharp is? Judging sharpness by pixel peeping can help, but it also can start us questioning everything about the lens in question. For me the ultimate test is whether I can make a sharp print with it. If the print is sharp without having to go nuts sharpening in post processing, the lens is sharp.
I couldn't see any test image in your post, and your last line seems to indicate you posted one.
Posted by Larry Puckett on August 14, 2008 at 2:48 PM
Andre--I suggest testing your lens using a standard setup like that described by Bill Chambers in his article here http://www.naturephotographers.net/articles1207/bc1207-1.html . You didn't mention what F-stop you are using and that can be a factor since the sharpest setting is probably around F8. Bill's test will tell you what kind of sharpness to expect with a given F-stop and focal length--Larry
Posted by David Bostedo on August 14, 2008 at 4:01 PM
As for what you consider sharp - if you have a lens that you like for sharpness, I'd try a very controlled setup for a comparison. One common thing to do is to tape a crisp new dollar bill (or Euro or Pound or whatever is handy) to a white wall. Then use a tripod and remote release or timer to take the pic at various apertures with both lenses. Move the tripod so the bill is as big in frame for the other lens (if need be). As Steve pointed out, this doesn't account for a bit of front or back focus, but it does give you a comparison point under good-to-ideal conditions. Front or back focus can be checked some other ways.
Just did a test. Went outside and set up the tripod at about 100ft from my Jeep. Next zoomed in at 500mm on a sticker with lettering set the timer and tested in AF and MF to make sure that the AF was okay. Doing it at f/6.3, 7.1, 8, 9, 10, & f/11. Then in the computer did heavy cropping to see the results. f/9-10 was the best seconded by f/6.3 and f/11 was awful while the rest were in the same ball park. Now to go out and test on live subjects.
Thanks all for the input. Funny thing is I tell others to test their glass to find the sweet spot.
Posted by Carol Hyman on August 15, 2008 at 12:31 AM
Andre,
The D200 from my own personal experience and from what I have read is also prone to a back-focus issue. I finally took my camera into Nikon and they did an adjustment. I need to do some formal testing (see Larry's comment on Bill Chamber's testing); however, the difference between what I'm getting with all of my lenses compared to what I WAS obtaining is amazing. I'm not familiar with the Sigma lens you are using. Also another comment. With the D200, I would suggest keeping the ISO 400 or UNDER. Lots of noise with the D200.
Andre Hi I have this lens for about 2 1/2 mths now and use the D300 with it.
I find this lens very sharp using it around the f8-f11 mark.
At the longer lengths of focusing 200meters @ onwards ther is sometimes a slight softness .This as I was told by NIKON can happen and what you need to do is a reset of your settings on the camera ???????. Yes but it works sometimes.
You can have a look at this link at photos I took with this lens and the TC 1.4 which was very very surprising.
Also I will be posting a couple of shots during the day taken with the lens for the travel book
Discussion
8 repliesI have been taking shots from 100-300 yrds. Is it possible that the farther away the subject the more prone to softness? I also had the in camera sharpening to off. I'm using the D200 and even with a SS of 800-1250 and ISO between 400-1250 at those distances soft is what I get. Will do some more tests at SS priority.
This shot is uncropped at 500mm, ISO 100, SS 200, f/7.1 hand held
Thoughts on this please.
At distances like that, the atmosphere can cause some softness. Humid days put texture in the air that softens distant shots. To do a better test for sharpness, mount the lens on a solid tripod and use a remote shutter release or the camera's self timer after focusing. Even with IS, camera shake while handheld can come into play as another cause of softness, and the tripod test will remove that possibility. I generally focus on a subject fairly close, a few feet beyond the lens MFD, so I have a lot of detail to pixel peep on. I like using a propped-up magazine, propping it so the bottom is closer and the top slants away somewhat. The contrast on the mag cover (or white inside pages) gives the autofocus something to grab onto easily, and reading words in an image is a very good test of sharpness.
All that being said, zooms are inherently softer than primes, in my experience, and stopping a lens down one stop usually produces a noticeable increase in sharpness.
And that being said, it's also just possible that model of lens is a bit soft, or that you have a soft copy and may need to exchange it.
But the tripod test usually separates the sheep from the goats. I like to use a subject that has some depth to ensure you'll be able to see the very sharpest portion of the DOF and make your judgment based on that. I don't like tests using flat subjects (exactly parallel to the sensor plane) because they can look a little soft if the camera is back- or front-focusing the lens a bit. If that happens, the test does not accurately gauge the inherent sharpness of the lens.
I'm also curious about what you're comparing it to when you say it is soft. Another lens? Your mind's eye and your own impression of what sharp is? Judging sharpness by pixel peeping can help, but it also can start us questioning everything about the lens in question. For me the ultimate test is whether I can make a sharp print with it. If the print is sharp without having to go nuts sharpening in post processing, the lens is sharp.
I couldn't see any test image in your post, and your last line seems to indicate you posted one.
Thanks all for the input. Funny thing is I tell others to test their glass to find the sweet spot.
The D200 from my own personal experience and from what I have read is also prone to a back-focus issue. I finally took my camera into Nikon and they did an adjustment. I need to do some formal testing (see Larry's comment on Bill Chamber's testing); however, the difference between what I'm getting with all of my lenses compared to what I WAS obtaining is amazing. I'm not familiar with the Sigma lens you are using. Also another comment. With the D200, I would suggest keeping the ISO 400 or UNDER. Lots of noise with the D200.
Good luck.
Carol
I find this lens very sharp using it around the f8-f11 mark.
At the longer lengths of focusing 200meters @ onwards ther is sometimes a slight softness .This as I was told by NIKON can happen and what you need to do is a reset of your settings on the camera
You can have a look at this link at photos I took with this lens and the TC 1.4 which was very very surprising.
Also I will be posting a couple of shots during the day taken with the lens for the travel book
http://www.pbase.com/avibram/beeeaters
Hope this helps
AVI
I'm looking at your link now as I right this. Very nice. How far were you from them? Are these shots as is or cropped? Next hand held or tripod?
I'm looking at your link now as I right this. Very nice. How far were you from them? Are these shots as is or cropped? Next hand held or tripod?