Sharpness

[NormanTan]

Hi CSer..

i jus wanna ask u guy what is than call sharp to u??i jus don understand what does sharp means to u guys>.< oso what do ppl means when they say zoom in to check for sharpness?what do they look out for?? how to know weather its sharp or not??Pls help me>.<Don scold me-.-.. thanks in advance^^




Regard,
NormanTan

[Rashkae]

Errr... Aside from the obvious "read a dictionary, look up the word sharp" the easiest answer would be when you can clearly see all the details of the subject without any blur.

[NormanTan]

So how would a lens that is not sharp be like when u zoom in? Blur??

[catchlights]

use your camera,
mount any lens on it,
mount your camera on a tripod,
aim at a subject with fine details
focus and lock it
I'm sure you know how to get correct exposure
shoot at f8

load the image into computer
open any image viewer software
zoom in 100%
you can see the clear definition of the fine details

this is sharpness...

once you see what is sharp... anything unlike this is call NOT SHARP

[windwaver]

Originally Posted by NormanTan So how would a lens that is not sharp be like when u zoom in? Blur??

You can put it that way but anything that is blown up 200% is considered pixel peeping. Besides, the perception of sharpness is different for different people.

[NormanTan]

Originally Posted by catchlights use your camera, mount any lens on it, mount your camera on a tripod, aim at a subject with fine details focus and lock it I'm sure you know how to get correct exposure shoot at f8 load the image into computer open any image viewer software zoom in 100% you can see the clear definition of the fine details this is sharpness... once you see what is sharp... anything unlike this is call NOT SHARP

Erm y shoot at f/8 eh?

[Fotophilic]

Originally Posted by NormanTan So how would a lens that is not sharp be like when u zoom in? Blur??

soft.

[NormanTan]

Originally Posted by Fotophilic soft.

soft? what do u mean by soft?? how does it/ will it look like?

[Fotophilic]

Originally Posted by NormanTan soft? what do u mean by soft?? how does it/ will it look like?

http://www.kenrockwell.com/nikon/50-.../sharpness.htm

I would like u to see under f/2, compare 1.8 AF at f/2 with the others. That is roughly wat i meant by soft.

[ssping83]

Originally Posted by NormanTan Erm y shoot at f/8 eh?

lens usually performs at it's best when stopped down to something away from it's maximum aperture..

and at f/8.. you get reasonably deep depth of field which increases perceived sharpness too..

correct me if i'm wrong..

[NormanTan]

sorry... but after looking at the kenrockwell.com webby, i still can't see the different=.= OMG!!

[catchlights]

it is so clear that you have not taken a sharp focus photo yet, that how you does not know how is a sharp focus photo looks like.

why don't just do a test and see it yourself like what I have suggested earlier?

[NormanTan]

Originally Posted by catchlights it is so clear that you have not taken a sharp focus photo yet, that how you does not know how is a sharp focus photo looks like. why don't just do a test and see it yourself like what I have suggested earlier?

this is crop from the above picture..i zoom this picture to 100% and crop it..is that the right way to crop it?? and is it sharp??


i took it at f8..using a 85mm f1.8

[Fotophilic]

Originally Posted by NormanTan sorry... but after looking at the kenrockwell.com webby, i still can't see the different=.= OMG!!

u surprised me. i tot the one at the F2 was pretty obvious already. Are u sure u can't see a diff? Are u looking at the picture i told u? If u really can't see a diff and was seeing the correct one, perhaps its a blessing in disguise for u.

Why don't u try performing the same test u did for ur 85mm f1.8 on ur 70-210mm f4-5.6. Rem, same focal length, same fstop, iso, etc. Everything constant except for lens. Try several f-stops and compare the 2 (e.g. 4.5, 5.6, 8). Perhaps the best way to let u see what is sharp and not sharp is to let u compare pictures. By right (no gurantee thou), ur 85 F1.8 should be sharper.

[NormanTan]

<<---- this is 100%zoom and crop... using my 70-210 at f/8 and 85mm which sharper??

[NormanTan]

<<<---this is done with the 85mm lens f/8 i feel that this is better than the previous 1

[Fotophilic]

y did u feel that the 85mm is better?

most lenses performs well ("sharp") at ard F8.

[NormanTan]

lol... so both the lens are sharp copy?? or which do u think is better?

[kingcrab]

Originally Posted by NormanTan this is crop from the above picture..i zoom this picture to 100% and crop it..is that the right way to crop it?? and is it sharp?? i took it at f8..using a 85mm f1.8

I think your 85mm 1/1.8 got alignment / focusing issue. This lens should be much sharper than this.

[NormanTan]

Originally Posted by kingcrab I think your 85mm 1/1.8 got alignment / focusing issue. This lens should be much sharper than this.

what do u mean by alignment and focusing issue can u elaborate more on it??