New Posts New Posts RSS Feed - depth of field/focus
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Check GunBroker.com for SWFA's No Reserve and No Minimum bid firearm auctions.

depth of field/focus

 Post Reply Post Reply   Topic Search Topic Search  Topic Options Topic Options
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/31/2012 at 21:16
bro.steve View Drop Down
Optics Apprentice
Optics Apprentice
Avatar

Joined: March/10/2012
Location: texas
Status: Offline
Points: 86
Talking with other squirrel hunters, many of our scopes have a difficult time with higher than 6 power in use without constant adjustment of the rear ocular. At 9X we have to focus it in, and then the image behind is blurred a bit. A few scopes have a depth of field that lessens this effect. We would like to have higher power to make those head shots, but at the distances we usually shoot, only the six power or less  keeps us from having to fine tune the focus--something a public hunting ground grey will seldom allow. Any favorite scopes that are not so shallow in depth of field?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: March/31/2012 at 23:52
Sparky View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire


Joined: July/15/2007
Status: Offline
Points: 3195
Originally posted by bro.steve bro.steve wrote:

  constant adjustment of the rear ocular.


What are you adjusting? And what type of scope are we talking about?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: April/01/2012 at 22:20
bro.steve View Drop Down
Optics Apprentice
Optics Apprentice
Avatar

Joined: March/10/2012
Location: texas
Status: Offline
Points: 86
Talking about several 3-9x40 scopes including one 4200 elite. Hard to shoot 9x at 25-35 yds. without sensitive adjustment. At 6x we can just set it and forget it, but had wanted the sight picture of the 9x on a squirrel's head. No problem if they are farther out there. Adjusted for up close, and the background is blurry. Rear ocular is fast focus type. Any scopes, regardless of price with greater depth of field that would not require fiddling with the focus?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: April/01/2012 at 23:10
Sparky View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire


Joined: July/15/2007
Status: Offline
Points: 3195
Sounds like you are using a center fire scope which usually has its parallax setting at 100yds. The 3-9 4200 Elite is a centerfire scope which will more than likely be blurry at 25-35 yds. Especially when used at higher magnifications. I would be looking at a rimfire scope that usually has its parallax setting for about 50yds. Or one with an AO which is what I use a Leupold 3-9x33EFR.

Also it sounds like the rear adjustment you are talking about is for focusing the reticle and not the image.

See third post on this topic and item #8.

http://www.opticstalk.com/what-exactly-is-parallax-anyway_topic5026.html

Also see "HOW TO SET UP A SCOPE!" in this topic as well.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: April/01/2012 at 23:14
Sparky View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire


Joined: July/15/2007
Status: Offline
Points: 3195
Two other good choices.

http://swfa.com/Weaver-3-9x32-Classic-Rimfire-Rifle-Scope-P3141.aspx

http://swfa.com/Weaver-25-7x28-Classic-Rimfire-Rifle-Scope-P600.aspx
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: April/03/2012 at 02:19
sholling View Drop Down
Optics Professional
Optics Professional
Avatar

Joined: May/24/2008
Location: Hemet CA
Status: Offline
Points: 892
Originally posted by bro.steve bro.steve wrote:

Talking with other squirrel hunters, many of our scopes have a difficult time with higher than 6 power in use without constant adjustment of the rear ocular.

Generally you have fixed focus, side focus, and adjustable objective (in front) scopes. The fixed focus should be reasonably in focus from close to infinity. A side focus scope is quick adjusting but they have a very-very limited depth of field. An adjustable objective scope falls in between with a depth of field of up to a few feet. I've only see one true rear focus scope. The rest just had a diopter adjustment at the rear. 

The two Weavers that Sparky mentioned are two of my favorites. The 2.5-7x28 is fixed focus and will be very fast on target. The 3-9x32 has an adjustable objective for finer focus and the cost of having to fiddle with the focus.


Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: April/03/2012 at 18:21
3_tens View Drop Down
Optics Jedi Knight
Optics Jedi Knight
Avatar

Joined: January/08/2007
Location: Oklahoma
Status: Offline
Points: 7182
bro.steve It is sounding more that you are trying to use magnification to get what better glass will give you. Clarity comes from good glass. Magnification magnifies the defects of weaker glass. 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: April/03/2012 at 18:39
sholling View Drop Down
Optics Professional
Optics Professional
Avatar

Joined: May/24/2008
Location: Hemet CA
Status: Offline
Points: 892
The Bushnell Elite 3-9x40 is a good scope, but if he's trying to use the diopter adjustment to focus for distance he's not using it right or he's using it too close. The rest of his scopes I can't speak to since they haven't been listed and for all I know could be Barskas, NcStars or BSAs which would explain everything. Wink

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: April/03/2012 at 20:41
bro.steve View Drop Down
Optics Apprentice
Optics Apprentice
Avatar

Joined: March/10/2012
Location: texas
Status: Offline
Points: 86
No, you hit it on the head, sholling--I am trying to use more magnification too close. Your comments about fixed focus probably have answered most of my concerns, as well as 50 yd. parallax setting. The older fixed focus scopes were probably the reason why we got away with using center fire scopes in the first place. And consider that way back then, those were the ones with one inch tubes, the .22 scopes being those pathetic smaller dia. jobs. Better glass, I can aspire to...would that be perhaps the Kahles?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: April/03/2012 at 20:46
bro.steve View Drop Down
Optics Apprentice
Optics Apprentice
Avatar

Joined: March/10/2012
Location: texas
Status: Offline
Points: 86
I do get a little confused by discussions implying that there is no such thing as depth of focus. IF binoculars have it in spades over center focus models, but even the center focus models differ, case in point being the Leica compacts--they have it. In rifle scopes I just wondered if some outperform others...
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: April/03/2012 at 21:18
sholling View Drop Down
Optics Professional
Optics Professional
Avatar

Joined: May/24/2008
Location: Hemet CA
Status: Offline
Points: 892
Do you remember the old fixed focus point and shoot cameras? Or have you seen modern fixed focus "sports" binoculars? You trade razor sharp focus for infinite depth of field and speed on target. The focus is still "good enough for the job". In the hunting world you don't need to count the critter's fleas when hunting, you just need to clearly see what you're shooting at in any light including minimal light. On the other hand if you're target shooting you need a razor sharp focus.

If you're shooting that close I'd look for a quality rimfire scope and research the minimum distance to focus.
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Similar Threads: "depth of field/focus"
Subject Author Forum Replies Last Post
Rifle scope depth of field question HFTshooter Rifle Scopes 1
best depth of field spot shooter Binoculars 16 6/22/2006 10:37:39 AM
bullet seating depth deerkiller Reloading & Ballistics 8 3/28/2007 8:15:06 AM
A good question... about depths Bigdaddy0381 Reloading & Ballistics 18 9/19/2007 8:09:59 AM
PROPER CHAMBER DEPTH ? hot30 Firearms 8 10/7/2007 7:22:03 PM
Seating depth question jason miller Reloading & Ballistics 17
seating depth question Brad4213 Reloading & Ballistics 8
Flat Field Ranging - 450 yards? RAG Laser Rangefinders 2
Field of View Gerry Atric Binoculars 5
tips for focusing reticle? eyesman Rifle Scopes 4


This page was generated in 0.328 seconds.