I am a 'singleton' in that I dont know anyone else who takes nature photographs to compare notes with in the real world (as opposed to the virtual world) so can I ask anyone to try and define what they call 'sharp'. e.g. Suppose you are looking at a birds eye, does it have to look sharp viewed at 100% (pixel for pixel) prior any sharpening or perhaps after sharpening, or perhaps you decide what is sharp and what isn't by the size you will print an image ?
The reason I ask is that I have in the recent past bought a second hand Sigma 300-800 and although I have a good tripod (Manfrotto 475B)I am not yet entirely happy with the sharpness I get which I am sure is down to me although my technique has certainly improved since I started using it. I use a Manfrotto 393 head which I have used for a couple of years without problem with 400mm lens, but I did wonder if this was a problem, however I think Tim uses one to very good effect. Although a print at A4 looks ok I always have a feeling that looking at the raw file at 100% it could be a bit better. Incidentally I am taking small birds at about 15 feet (FF sensor) so also have to have a tube fitted to decrease the minimum focus slightly, I normally try and use f8 and the focus point seems good. I know a prime would be sharper but I prefer zooms, especially as a lens of this length is not easily portable (and I am not that fit ;) I therefore tend to stay in one place when using the 300-800 so a zoom is then much easier to compose with
Terry
Posted by Tim Munsey on September 3, 2006 at 3:14 PM
Watch it, you'll start a gimble war. I'm no techie with regards to lenses, but what is often suggested is to take pics of some text, I guess you need a control of a lens that you feel is sharp to compare with your sigmonster.
For printing I believe it is suggested that you over sharpen, I hope John McT will advise.
Tim
Posted by John MacTavish on September 3, 2006 at 5:31 PM
Sharpness is, at the best of times, a complex subject.
Percieved sharpness, as opposed to pure sharpness, can be be influenced by light direction, strength of light, contrast and subject matter.
Pure sharpness is not influenced by any of the above, it is just a plain scientific fact that is fairly boring unless you like comparing groups of parallel lines.
Acceptable sharpness is where we get to in photography, what's acceptable to one person is sometimes percieved to be under or over sharpened to someone else.
Things that make sharpening look over sharpened are halos around edges with highish contrast, dew effect on grass or other fine detailed areas, noise levels being excagerated (sharpening edges also sharpens the edges of noise patterns if you're clumsy, or in a hurry, or both!)
I tend to view my shots at 50% as opposed to 100% simple because sharpness or the lack of it is easier for me to see at that size .
Given that you are shooting your subject in good light (by good I mean light that will show contrast to good effect) and that you have your lens tethered with a good support you should be able to see instantly if a shot is sharp or not....if it's sharp it will pop, even an unsharpened RAW file will do this if it's been nailed. Further sharpening will compliment it but don't over do it.
For printing purposes some say it is not a bad thing to over sharpen........I say it is. You can get away with a bit more sharpening for printing onto canvas or semi gloss paper, but if you over do it with gloss paper then the print will look terrible. As a general rule if it looks good at 50% on screen it should look good at any size you print it too. Be carfull not to be doing any editing or sharpening in PS at sizes other than 25, 50, 75 or 100% If you go for inbetween %ages like 33.3 you get jaggies appearing on your straight lines, but only on your screen.
John, your comment "As a general rule if it looks good at 50% on screen it should look good at any size you print it too." was exactly the kind of advise I was looking for. I normally view for sharpness at 100% but will give it a try at 50%
Just to concur with John here, when I teach PS these days I actively discourage people from viewing at 100%, unless you are 10 foot away from the screen, viewing at 100% is akin to looking at a billboard poster from a couple of feet away.
Judge sharpening at 25 or 50%, 25% is (at normal screen resolutions, i.e 1024 x ###) very near to viewing at print size.
You don't say which sharpening method you are using which makes it hard to help on the PP side, my prefered method is a small amount of capture sharpening, a touch of creative sharpening (rarely needed) plus a final sharpening for the output device/method.
Long lens technique is important with a lens the size of the 3-800 and takes a lot of practice to get it right, (mirror slap is often to blame for slight softness at certain shutter speeds). a lot of things conspire against you when using long lenses.
All the best
Phil
Posted by Dave Courtenay on September 4, 2006 at 9:29 AM
I think the first time somebody buys a super zoom/telephoto the initial images are dissapointing and an understanding of long lense use takes a while to get to grips with,Try it on a beanbag instead of a tripod and all your images will be pin sharp,My brother bought a sigmonster and had to up grade to a bigger tripod and head to get sharp images
Phil, "Judge sharpening at 25 or 50%, 25% is (at normal screen resolutions, i.e 1024 x ###) very near to viewing at print size. " I hadn't thought of it that way - thanks. The reason I didn't say how I sharpen was because I am reasonably happy with doing that and I was really more interested in how people decide if they have an acceptably sharp image straight from the camera and both your and Johns suggestion about looking at 50% is very interesting to me.
Dave, thanks and I will try your suggestion of the bean bag to see how that goes. Its nice to know (in a strange kind of way) that I am not the only one who has come across this problem.
If you have a browse around the main NPN site you should be able to find a few articles about sharpening and long lens "technique" in the archives and in the "101" sections (US Speak for tutorials) - they should provide you with a few pointers to get going with.
BTW, don't fall into the common trap of confusing "sharpening" with a "sharp" image ie an image which is focused properly and which has no blur due to camera, lens or subject movement. To evaluate an image to see if it has been correctly focused etc, I will usually use something that I know should have a well defined edge - eg an eye/pupil or a wing/beak/leg.
Discussion
8 repliesThe reason I ask is that I have in the recent past bought a second hand Sigma 300-800 and although I have a good tripod (Manfrotto 475B)I am not yet entirely happy with the sharpness I get which I am sure is down to me although my technique has certainly improved since I started using it. I use a Manfrotto 393 head which I have used for a couple of years without problem with 400mm lens, but I did wonder if this was a problem, however I think Tim uses one to very good effect. Although a print at A4 looks ok I always have a feeling that looking at the raw file at 100% it could be a bit better. Incidentally I am taking small birds at about 15 feet (FF sensor) so also have to have a tube fitted to decrease the minimum focus slightly, I normally try and use f8 and the focus point seems good. I know a prime would be sharper but I prefer zooms, especially as a lens of this length is not easily portable (and I am not that fit ;) I therefore tend to stay in one place when using the 300-800 so a zoom is then much easier to compose with
Terry
For printing I believe it is suggested that you over sharpen, I hope John McT will advise.
Tim
Percieved sharpness, as opposed to pure sharpness, can be be influenced by light direction, strength of light, contrast and subject matter.
Pure sharpness is not influenced by any of the above, it is just a plain scientific fact that is fairly boring unless you like comparing groups of parallel lines.
Acceptable sharpness is where we get to in photography, what's acceptable to one person is sometimes percieved to be under or over sharpened to someone else.
Things that make sharpening look over sharpened are halos around edges with highish contrast, dew effect on grass or other fine detailed areas, noise levels being excagerated (sharpening edges also sharpens the edges of noise patterns if you're clumsy, or in a hurry, or both!)
I tend to view my shots at 50% as opposed to 100% simple because sharpness or the lack of it is easier for me to see at that size .
Given that you are shooting your subject in good light (by good I mean light that will show contrast to good effect) and that you have your lens tethered with a good support you should be able to see instantly if a shot is sharp or not....if it's sharp it will pop, even an unsharpened RAW file will do this if it's been nailed. Further sharpening will compliment it but don't over do it.
For printing purposes some say it is not a bad thing to over sharpen........I say it is. You can get away with a bit more sharpening for printing onto canvas or semi gloss paper, but if you over do it with gloss paper then the print will look terrible. As a general rule if it looks good at 50% on screen it should look good at any size you print it too. Be carfull not to be doing any editing or sharpening in PS at sizes other than 25, 50, 75 or 100% If you go for inbetween %ages like 33.3 you get jaggies appearing on your straight lines, but only on your screen.
John
I'm not going to try and define it, just point you in the direction of an article t help you understand it..
Ron Bigelow's Sharp article
John, your comment "As a general rule if it looks good at 50% on screen it should look good at any size you print it too." was exactly the kind of advise I was looking for. I normally view for sharpness at 100% but will give it a try at 50%
Terry
Judge sharpening at 25 or 50%, 25% is (at normal screen resolutions, i.e 1024 x ###) very near to viewing at print size.
You don't say which sharpening method you are using which makes it hard to help on the PP side, my prefered method is a small amount of capture sharpening, a touch of creative sharpening (rarely needed) plus a final sharpening for the output device/method.
Long lens technique is important with a lens the size of the 3-800 and takes a lot of practice to get it right, (mirror slap is often to blame for slight softness at certain shutter speeds). a lot of things conspire against you when using long lenses.
All the best
Phil
Phil, "Judge sharpening at 25 or 50%, 25% is (at normal screen resolutions, i.e 1024 x ###) very near to viewing at print size. " I hadn't thought of it that way - thanks. The reason I didn't say how I sharpen was because I am reasonably happy with doing that and I was really more interested in how people decide if they have an acceptably sharp image straight from the camera and both your and Johns suggestion about looking at 50% is very interesting to me.
Dave, thanks and I will try your suggestion of the bean bag to see how that goes. Its nice to know (in a strange kind of way) that I am not the only one who has come across this problem.
Terry
If you have a browse around the main NPN site you should be able to find a few articles about sharpening and long lens "technique" in the archives and in the "101" sections (US Speak for tutorials) - they should provide you with a few pointers to get going with.
BTW, don't fall into the common trap of confusing "sharpening" with a "sharp" image ie an image which is focused properly and which has no blur due to camera, lens or subject movement. To evaluate an image to see if it has been correctly focused etc, I will usually use something that I know should have a well defined edge - eg an eye/pupil or a wing/beak/leg.