Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-16-2009, 03:32 PM   #1
Forum Member




Join Date: Jul 2009
Location: Kentucky
Posts: 62
Another nooob question...

I've seen the term "step down" used alot, and I'm not so sure I know what it means. I bought a cheap Tamron 28-80mm lens from B&H ($49!) and the only review I could find said that the IQ improves if you step it down. A little insight please?

12-16-2009, 04:01 PM   #2
New Member
Novocain's Avatar

Join Date: Nov 2009
Location: Pittsburgh PA
Photos: Gallery
Posts: 21
It refers to stepping down the aperture from the widest available opening to smaller openings.

I do not understand the science behind the IQ improvement. Maybe someone else can shed some light.
12-16-2009, 04:36 PM   #3
Veteran Member




Join Date: Sep 2007
Location: La Crescenta, CA
Posts: 7,450
Generally the term is "stop down." Most lenses have an optimal aperture with regard to IQ... you can see this in their MTF resolution charts and so on. Stopping down is the act of selecting an aperture narrower than the widest.

For an explanation of "stops," look here.
12-16-2009, 09:09 PM   #4
Veteran Member
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
And in case you're unfamilair with the basics of exposure, aperture , aka f-stop, is how big the opening inside the lens is. In an fully automatic mode, the camera chooses this for you. If you want to choose your own aperture, use av mode, and the dial then lets you do so. Smaller numbers are larger apertures; stopping down means moving to larger numbers (smaller apertures). Typically best results are obtained about 3-6 clicks of the wheel form the largest aperture (smallest number). In fully automatic mode, it generally does htis for you, as the camera "knows" this too. It would only choose to shoot at the largest aperture if that was the only way to get a high enough shutter speed.

12-16-2009, 09:15 PM   #5
Loyal Site Supporter
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 12,230
QuoteOriginally posted by Marc Sabatella Quote
And in case you're unfamilair with the basics of exposure, aperture , aka f-stop, is how big the opening inside the lens is. In an fully automatic mode, the camera chooses this for you. If you want to choose your own aperture, use av mode, and the dial then lets you do so. Smaller numbers are larger apertures; stopping down means moving to larger numbers (smaller apertures). Typically best results are obtained about 3-6 clicks of the wheel form the largest aperture (smallest number). In fully automatic mode, it generally does htis for you, as the camera "knows" this too. It would only choose to shoot at the largest aperture if that was the only way to get a high enough shutter speed.
And Pentax includes MTF program mode which will keep the lens at one or two ideal apertures with any Pentax lens that can tell the camera what the best MTF aperture(s) are. Think FA or later.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, pentax help, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Can I ask a question ? Lloydy General Talk 1 04-27-2010 05:09 PM
Question curatolo Troubleshooting and Beginner Help 4 03-21-2010 04:24 PM
K-m question adwb Pentax DSLR Discussion 3 10-30-2009 12:13 PM
K7 question dafiryde Pentax DSLR Discussion 29 08-05-2009 12:56 PM
An Answer to a question and a question. granitic Pentax DSLR Discussion 5 02-23-2007 09:28 AM



All times are GMT -7. The time now is 09:58 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top