Kbeaner

Im getting ready to buy a new scope, it will be a Leupold. I want to hear some opinions on the objectives, 40 and 50. We own several 50mm, and a few 40s as well. Though it seems we always have more trouble getting the 50s dialed in. Is there really THAT much more advantage has far as light transmission is concerned? And while Im at it...any recommendations on which Leupold for a .300 RSAUM? Its been a while since I bought any Leupold and you know how times change as well as products (not always for the better) thanks.

game4lunch

Your sight rings moght answer this for you. I had to go with 40mm because the 50's would hit the barrel with the scope rings that came with the gun. (Ruger . . . love it!)
I can't see any reason to go with the 50mm unless it is a high powered variable say up to 14 or more. The higher you go in power with any optics, the more light you loose so the larger objective will let in lore light. Look at the objective on most spotting scopes.
As far as which scope? I went to buy a Leupold (only scope I'd used for 30+ years) and came home with a Nikon Monarch on it. Much better light gathering, clearer view, easier object chase, and less money. Worth a look.

nchawkeye

Kbeaner...I called Leupold a few years back and asked the difference between 40 and 50 mm objectives...The 50 lets in about 3% more light if the lenses have the same coatings etc...

Now, what does this mean to us deer hunters?? I bought a VX-II 3x9x40 and my brother (the one always wanting bigger/better...) bought the
VX-III 3.5x10x50 for his .280...

Let me make a couple of points as I have hunted and killed deer with his setup...
1) The 50mm affects your cheek weld on the stock, not as bad as see through mounts, but enough that when I shoulder his gun I have to move my face to look through the scope...
2) I can tell no difference in how "late" you can see to shoot deer...In other words, in a quality scope a 40 mm is plenty bright to shoot even as much as 15-20 minutes after legal shooting time is over....This in itself makes a 50 mm a mute point to me...
3) As you get older your pupils will not dialate as well as when you are younger....Guess what, that little bit of extra light the 50 mm gives ain't going to help if your eyes can't use it....

The biggest improvement I have made to my two Leouplds on my deer rifles were to return to Leupold and have the Heavy Duplex reticle installed...The crosshairs are what fade in low light, more so than the deer.

One other point...The Leupolds I have are the older VX-IIs...The current VX-I has the same glass as I have...The new VX-II and VX-IIIs let in even more light than mine would, but mine is plenty bright...I'd go with the 40mm...

Hope this helps...

bigcountry

What alot of people don't understand is a 50mm resolves more at far distances. In other words for varmit hunting, I highly suggest 50mm. At 500 yards, instead of a groundhog looking like a fuzzy blob, you can actually make it out. You might be able to actually id a deer antlers at 500 yards. A 50mm has 36% more area also, so lets in more than 3% light. I wonder if that 3% is linear or logrithmic.

stubblejumper

I have never seen the need for a 50mm scope,and I don't like to mount my scopes as high as is required with a 50mm objective lens.If I need a brighter scope,I buy a scope with better quality coatings and lenses.

HEAD0001

IMO their is a difference between light gathering, and light transmission. If the light is not transmitted to the eye, then it is of no value(actually a negative). Again IMO if you go to the 50mm objective, then go with the 30mm body to transmit this light to the eye.

The second and thirdfactor with light transmission is lens quality, and lens coating quality. Obviously the better the lenses and the better the coatings, then the more light transmission to the eye.

Bottom line, buy the best glass you can afford. A one inch tube-40 mm Swarovski will transmit more to the eye than a wiz bang 50 mm, with a 30 mm tube at 32 power.

Determine the power you need (most people buy too much). I would rather have a straight 6X Swarovski than a 3.5 X 10 Leupold. Tom.

Colorado Luckydog

Check this out...

http://www.leupold.com/hunting-and-shooting/products/scopes/vx-l-riflescopes/vx-l-4-5-14x50mm/

Want a 50mm that sits low, you got it. It will sit as low as a 30mm, but it's gonna cost ya!

trailer

I haven't found any advantage using a 50 mm for hunting during legal hours that a 40 or 42 mm couldn’t do...

bigbulls

A humans eye will only dialate to aproximately 7mm in diameter in pitch black total darkness. At early and last light your eye will be dialated to about 4mm - 5mm if you are a young healthy human with no eye problems. Less as you get older and less the brighter it is.

Divide the objective lense diameter by the magnification to get the scopes exit pupil diameter. Example... a 3-9X40 scope will have an exit pupil of 13.3mm at 3 power- 4.4mm at 9 power.

If a scope has an exit pupil larger than what your eye is dialated then that light is wasted and not absorbed by your eye and will not appear any brighter than the same magnification with a smaller objective. Example... a scope set at9 power will appear equally bright regardless if your arehave a 40mm or 50mm objective lense.Because with the 40mm the exit pupil diameter is 4.4mm which is just about exactly what your eye will be dialated at last shooting light and with the 50mm lense the scopes exit pupil will be 5.5mm which will likely be larger than what your eye is dialated.

If the scopes exit pupil is smaller than what your eye is dialated then your eye/ brain will interperate this as less bright. Example a scope set at 12 power will be brighter with a 50mm objective lense than it would be with a 40mm objective lense. Because with a 50mm lense the scopes exit pupil will be 4.2mm and with a 40mm lense it would only be 3.3mm.

So figure out how much magnification you are going to purchase and select your ebjective diameter accordingly.


Just a note.... There is no such thing as light gathering. A scope doesn't hop off the rifle and go out and gather up light as if it were picking berries. A scope only TRANSMITS light.

bigcountry

Well, photons move. The larger the objective is to pick up the photons, the more bright an object will appear. Same as with satillite dishes, same physics apply. But I understand what your saying. If you are viewing say a licence plate at 500 yards, and it appears very bright contrasted to without. It would be brighter if you walked up to it to the point its at the same magnification. Photons flying thru lenses concentrating polarized light at your lenses loses some brightness, clarity, etc. As some recent independent tests have concluded, scopes claiming 95% is pure bull. Its more like 92% as John Barsness recently reported. I believe that.