Riflescope Depth of Field above 10X: 42mm vs 50mm

[UBear]

Hi All, I'm aware of most topics usually discussed with scopes regarding optical performance but, I can't recall learning much on this subject for scopes.

First things first... Is it even an issue for big game hunting?

Second, assuming all else is equal between two scopes (3-15x42 vs. 3-15x50)... will one be better for counting points on a mule deer at say, 700 yards laying in tall brush or maybe standing 10 feet into the tree line?

Another way to ask this might be... Would parallax adjustment be less touchy with the smaller objective?


Thanks for any input!

 

[UBear]

Guessing I went about that wrong... please let me try again:
Is there ever any "optical" advantage/benefit to going with the smaller objective option?

Some examples;
Zeiss V4 4-16x44 vs. x50
Vortex LHT 3-15x42 vs. x50
Leupold VX-6HD 3-18x44 vs. x50
NF ATACR 4-16x42 vs. x50

 

[duckpopper]

Bigger objectives theoretically give you more resolving power and will provide a brighter image. I’ve never noticed any difference in depth of field between objective sizes. Parallax quirks seem to be related to specific scope designs/Overall length vs the objective size. Just my opinion

 

[UBear]

Thanks Duckpopper, appreciate the input. Matches my limited experience as well.

After many many years I'm finally moving up from a 3-9x scope and trying to avoid any regrets from added 3/4 -1 lbs weight of a bigger scope

 

[duckpopper]

One other thing I forgot to mention, but for many of us, a smaller objective will certainly allow for a lower mounting height on your rifle which provides a better cheek weld and easier eye placement. I’ve dropped down from the 50mm objectives to 42-44 and my ease of eye placement behind the scope and shooting comfort have gone up considerably. With the quality of glass these days you don’t need 50+ mm of objective to see past legal shooting light.

You won’t regret the step up in power as long as you don’t go too far. I’ve found the 4-16 power range covers all my bases from 50 yards to well past 1000 and its not so high of a mag range that I can’t find animals close or require a huge objective at max power to get a good exit pupil.

 

[Sobrbiker]

Duck nailed it. Mounting options for proper repeatable position enhance accuracy, and that’s priority in an aiming device.

As far as depth of field, I like to be able to have a more sensitive focus at high power. The ability to focus crisply on an object a short distance in front of the target allows me to see the down range mirage best. Years of precision rifle comps have taught me that the down range mirage is the best practical indicator of what wind hold needs to be.

 

[UBear]

Thank you both... your input has helped!! I was caught up with over-analyzing & convincing myself I might as well get the 50mm and just deal with any physical negatives (like height).

It was actually the mounting height issue that made me finally post this thread lol... instinct was to go with the 42/44mm options for the reasons you mentioned but, that just kept seeming kinda contrary to the "optics upgrade" side of the coin. Oh well, i'm good at being contrary

Sobrbiker, I appreciate you sharing that part about focus. That's the first time I've read of someone liking a sensitive focus or talking about how it can be a good thing but, your explanation makes perfect sense to me.

 

[Rick Hallenbeck]

I have found personally that is comes down to edge of glass clarity, how sharp and true the image stays as it reaches the edge of the objective lens . Cheap glass that is clear and true in the center but begins to deviate as the image reaches the edges will never compare to good glass in a smaller objective that is true to the edge. Also for me the exit pupil and eye relief is a prime concern as was stated.

Duckpopper you ever sell the TRG?

 

[Alienx]

Guessing I went about that wrong... please let me try again:
Is there ever any "optical" advantage/benefit to going with the smaller objective option?

Some examples;
Zeiss V4 4-16x44 vs. x50
Vortex LHT 3-15x42 vs. x50
Leupold VX-6HD 3-18x44 vs. x50
NF ATACR 4-16x42 vs. x50

I'm in the same boat and was going to ask almost the identical question. Looking specifically at the two VX-6's you have mentioned. Assumed the 50mm is "better" but maybe the 44mm is all I need??? (Also available now where the other is sold out)