Quality question. - DPChallenge Forums

Sigma 24-70mm f/2.8 EX Aspherical DF for Canon

12/19/2003 06:21:06 PM · #1

Since I bought my 300D, time has been real tight so I haven't had time to experiment much.. The two images below was shot with a Sony Mavica, handheld. The thing I was wondering is, will the crosshatch still be there in the extreme out of focus for close ups? I'm hoping the 300D will do better than this, but some say its a product of digital.

Message edited by author 2003-12-19 18:21:33.

magnetic9999

Canon EOS-20D

12/19/2003 06:23:23 PM · #2

depends on the lens, but i dont think so
:)

drewdraw1

Olympus C-750UZ

12/19/2003 06:25:21 PM · #3

If I could ever figure out how to upload some shots.I have some tight shots like that w/o the cross hatching.

kirbic

Canon EOS R5

Canon RF 24-70 f2.8 L IS

12/19/2003 06:37:41 PM · #4

Echo Mag's thoughts... almost no matter the lens you use you should not see anything like this on the 300D.
The quality of the out-of-focus area is what is usually referred to as "bokeh", and this is "very bad bokeh". A sharp, highly color-corrected lens does not necessarily produce great bokeh, and a poorly corrected, average lens does not necessarily produce bad bokeh either. It's a function of lens design. One factor affecting bokeh is how the lens is corrected for spherical aberration. If I remember this correctly, a slight undercorrection is better for background bokeh, worse for foreground; overcorrected is the opposite.

I've never seen exactly the effect your two shots show; it's really quite distracting. I'd certainly like to know what's the cause of it. It definitely has something to do with the optical system, but exactly what, who knows?
I do know that you get some really wierd bokeh effects when you have a central obstruction, e.g. a catadioptric (mirror) lens. You get ring-shaped features from out-of-focus point light sources, and can get "double vision" effect on OOF lines. Again very distracting.

jmritz

Fujifilm X30

Custom Made Pinhole

12/19/2003 06:48:34 PM · #5

My Sony 717 has never done anything like this strange effect you have there. Same with the S75 Sony I have and I have taken hundreds of shots with both. Is this without extra lenses?

Message edited by author 2003-12-19 18:49:10.

soup

Canon EOS-30D

Canon EF 17-40mm f/4L USM

12/19/2003 06:50:06 PM · #6

an example of a 'no' answer maybe?

closer background objects

Message edited by author 2003-12-19 18:51:41.

12/19/2003 06:50:43 PM · #7

Wow Fritz, thats a fantastic answer. I'm still learing this digital world so I'm absorbing everything right now. I need to go burn a few hundred frames on meaningless subjects. I'm off work starting now until Jan. 5th, so thats what I'll do. As far as the bad optics, the Sony Mavica, in my opinion is only good for webpage graphics, which is why I bought it, but after your explaination, I want to experement more with it more.

12/19/2003 06:54:17 PM · #8

John, This is with an old FD88 with a fixed lens. Other than the FD88, I've only done film work so I'm trying to learn what my hurdles are I have to overcome since going digital.