Why does it seem like the 3-9 is really the only scope that's easy to find with a 50mm objective? is there a reason to only have a 40 or 44mm?
It seems like 40 is by far the most popular. I'm not sure why people wouldn't want that little bit extra view?
I'd really like a ~6-18x50, prefer Nikon or Redfield. But not so easy.
A few reasons:
1. Cost - If made to the same quality level, they cost more to build than smaller objectives.
2. Appearance - Some just do not like the look of them, so avoid them. Manufacturers like to sell what they make, so avoid unpopular features.
3. Scope Height - Some do not have the stock to hold their cheek tight to the stock, and get their eye up to the height of a high scope.
4. Functionality - In many scopes and under daylight conditions, the 50 mm objective adds no value. Take the basic 3-9X scope. A 50 mm objective will give an exit pupil of 50/3 = 16.6mm at 3X, and 50/9 = 5.5mm at 9X. A young person can use up to 8 mm exit pupil (young eyes can open up more), while an older fart can probably only use 4mm. So in this example neither an old or young can even use the exit pupil at 3X, and only the young person at 9X. Also neither can use it during daylight, as there will be too much light even for 4mm. Bottom line is that the big objectives only help at high powers and only in dimmer light, and in some cases only for younger eyes.
On a similar topic, a lot can be made of having fully coated lenses that give 98% transmission of light instead of 95% or whatever. The reality is that in 99% of the cases the scope is used, it makes no difference, because your eye has too much light already, and will not make use of the extra light transmission.
On view, a larger objective may or may not give it. Extra view is likely only useful for hand holding on game, where you use a low power anyway which has lots of view.
