What exact specs to look for in a lens?

What you see is what you get, including photography, displays, and video equipment.

Moderators: Dposcorp, SpotTheCat

Re: What exact specs to look for in a lens?

Postposted on Tue Apr 06, 2010 7:40 pm

mattsteg wrote:Guys, enough with the RAW holy war. There are plenty of good reasons to choose to shoot RAW (either routinely or for a specific shoot) and plenty of good reasons to shoot straight to jpeg (either routinely or for a specific shoot).

Lex: what looks "funny" about your Raptors photos? They don't strike me as particularly strange.

Magnification is the size (in specifications at closest focus) of the image on your camera's sensor relative to the size of the object in real life. With 1:1 or 1x magnification you can fill the entire image with something the size of the image sensor - a little less than an inch wide for "crop" cameras. With 1:2 magnification you are at half size, so you can only focus close enough to fill the image with something a couple of inches wide. 1:3.5 would be less capable still (in terms of magnification). More than 1x magnification in a lens (without added accessories) is pretty rare. I can think of a Canon lens that does it, but that's it for SLR lenses i know of (and that lens is very specialized).


That's because I only uploaded the good ones.

Here are some that will show what I'm talking about:

http://s978.photobucket.com/albums/ae26 ... g&newest=1
http://s978.photobucket.com/albums/ae26 ... g&newest=1
http://s978.photobucket.com/albums/ae26 ... g&newest=1
http://s978.photobucket.com/albums/ae26 ... g&newest=1
. . . this is the digital projection of your mental self. . . .

Darth Lex-idius vs. Obi Lex kanobi
lex-ington
Minister of Gerbil Affairs
 
Posts: 2920
Joined: Fri Apr 25, 2003 10:59 pm
Location: Toronto, ON

Re: What exact specs to look for in a lens?

Postposted on Tue Apr 06, 2010 8:12 pm

Your shutter speeds are a bit low on a few of those. There might be a bit of blurring due to image stabilization artifacts or subject movement. The shots with the subjects on the close side of the court may also be close enough and at a depressed angle so that the shallow depth of field at f/2.8 doesn't put the heads and feet in focus at the same time. Honestly, they look decent to me.


mattsteg wrote:More than 1x magnification in a lens (without added accessories) is pretty rare. I can think of a Canon lens that does it, but that's it for SLR lenses i know of (and that lens is very specialized).
The MP-E 65mm f/2.8 1-5x Macro Photo is definitely a very specialized lens. It's lowest magnification is 1:1 - which is the closest that most macro lenses can get. It then gets as close as 5:1 :o. It cannot focus on anything more than a foot away from the camera.

Regular lenses can increase magnification somewhat by using extension tubes or a 1.4x teleconverter.
JustAnEngineer
Gerbil God
Gold subscriber
 
 
Posts: 15591
Joined: Sat Jan 26, 2002 7:00 pm
Location: The Heart of Dixie

Re: What exact specs to look for in a lens?

Postposted on Tue Apr 06, 2010 10:13 pm

lex-ington wrote:
mattsteg wrote:Lex: what looks "funny" about your Raptors photos? They don't strike me as particularly strange.


That's because I only uploaded the good ones.

Here are some that will show what I'm talking about:

http://s978.photobucket.com/albums/ae26 ... g&newest=1
http://s978.photobucket.com/albums/ae26 ... g&newest=1
http://s978.photobucket.com/albums/ae26 ... g&newest=1
http://s978.photobucket.com/albums/ae26 ... g&newest=1


I'm still not sure what you're talking about either. Aside from the perspective flattening which is normal for teles, I can't see anything strange going on. Could you perhaps describe an example explicitly?
Last edited by Voldenuit on Tue Apr 06, 2010 10:28 pm, edited 1 time in total.
Wind, Sand and Stars.
Voldenuit
Minister of Gerbil Affairs
 
Posts: 2455
Joined: Sat Sep 03, 2005 11:10 pm

Re: What exact specs to look for in a lens?

Postposted on Tue Apr 06, 2010 10:17 pm

lex-ington wrote:
mattsteg wrote:Guys, enough with the RAW holy war. There are plenty of good reasons to choose to shoot RAW (either routinely or for a specific shoot) and plenty of good reasons to shoot straight to jpeg (either routinely or for a specific shoot).

Lex: what looks "funny" about your Raptors photos? They don't strike me as particularly strange.

Magnification is the size (in specifications at closest focus) of the image on your camera's sensor relative to the size of the object in real life. With 1:1 or 1x magnification you can fill the entire image with something the size of the image sensor - a little less than an inch wide for "crop" cameras. With 1:2 magnification you are at half size, so you can only focus close enough to fill the image with something a couple of inches wide. 1:3.5 would be less capable still (in terms of magnification). More than 1x magnification in a lens (without added accessories) is pretty rare. I can think of a Canon lens that does it, but that's it for SLR lenses i know of (and that lens is very specialized).


That's because I only uploaded the good ones.

Here are some that will show what I'm talking about:

http://s978.photobucket.com/albums/ae26 ... g&newest=1
http://s978.photobucket.com/albums/ae26 ... g&newest=1
http://s978.photobucket.com/albums/ae26 ... g&newest=1
http://s978.photobucket.com/albums/ae26 ... g&newest=1
Could you please say what you think is wrong with those? Other than not being super sharp, I don't see what the problem is.
...
mattsteg
Gerbil God
 
Posts: 15761
Joined: Thu Dec 27, 2001 7:00 pm
Location: Applauding the new/old variable width forums

Re: What exact specs to look for in a lens?

Postposted on Wed Apr 07, 2010 12:27 am


I dunno about "surreal"...I do see the "pasted on" look from the flattened perspective, along with the problem in capturing movement -- the floor and its details, highlights, etc. are sometimes sharper than the human subjects.
He who laughs last, laughs first next time.
ludi
Gerbil Elder
 
Posts: 5485
Joined: Fri Jun 21, 2002 10:47 pm
Location: Sunny Colorado front range

Re: What exact specs to look for in a lens?

Postposted on Wed Apr 07, 2010 1:05 am

ludi wrote:
lex-ington wrote:I dunno about "surreal"...I do see the "pasted on" look from the flattened perspective, along with the problem in capturing movement -- the floor and its details, highlights, etc. are sometimes sharper than the human subjects.


The camera AF probably locked onto the floor instead of the humans.

For all the talk (and ads, oh ads ad nauseum :D ) about "intelligent" AF and exposure systems, cameras can only use what algorithms they are programmed with, so can never be as smart as the human behind the viewfinder. This is probably exacerbated by the wide (for a tele) aperture and the shallower depth of field in front of the focal plane.

To get around this, the OP could
1. manually select AF points, and make sure they are centered over the humans
2. prefocus
3. Select a smaller aperture to increase the DOF

Each approach has its benefits and drawbacks, and you might end up combining or switching between them.
Wind, Sand and Stars.
Voldenuit
Minister of Gerbil Affairs
 
Posts: 2455
Joined: Sat Sep 03, 2005 11:10 pm

Re: What exact specs to look for in a lens?

Postposted on Wed Apr 07, 2010 6:09 am

It appears to me by the comments made that something is very wrong with either my monitor (Acer H243H) or my vid-card (Sapphire 5750 1GB w/ Catalyst 10.3) or a mixture of both. I will have to check my photobucket from work to see if the pictures are the way they look on my monitor.

Thanks for all the feedback. I'll be trying what Voldenuit said and play around with the manual settings, or maybe try the auto shutter speed setting and manually set the aperture.
. . . this is the digital projection of your mental self. . . .

Darth Lex-idius vs. Obi Lex kanobi
lex-ington
Minister of Gerbil Affairs
 
Posts: 2920
Joined: Fri Apr 25, 2003 10:59 pm
Location: Toronto, ON

Previous

Return to Visual Haven

Who is online

Users browsing this forum: No registered users and 3 guests