Gully Posted June 24, 2009 Report Share Posted June 24, 2009 I've seen comments that a 25mm scope tube doesn't let any less light through than a 30mm, so if not what's the difference? I'm looking at a Schmidt & Bender 8x56 and wondering which to go for. Quote Link to comment Share on other sites More sharing options...
Dunkield Posted June 24, 2009 Report Share Posted June 24, 2009 What's the diffrence? 5mm In a PW mythbusting test the answer was nothing at all, some say 30mm came about to give more adjustment, others say it is fashion. If the scope is good enough even with a 25mm tube it will pull the light in, it has more to do with glass quality/coatings than lens or tube size (IMHO) If he doesn't see this and reply, PM Dead Eye Ive as I think he has both 25mm and 30mm S&B's Quote Link to comment Share on other sites More sharing options...
lineshooter Posted June 24, 2009 Report Share Posted June 24, 2009 I have both and to be honest, in normal daylight conditions there is no difference, at dusk you may get a few minutes more time in the field with the larger size tube, but you could also get that with a 1 inch tube and a bigger objective lens. I brought my 30mm bodied Mtc Viper because they were the in thing at the time, as stated earlier lens quality is really the decider. Quote Link to comment Share on other sites More sharing options...
Nocrimp Posted June 24, 2009 Report Share Posted June 24, 2009 Light transmission is mostly dependant upon the surface area of the objective lens and has nothing to do with the tube diameter. 30mm tunes facilitate the potential; for larger MOA adjustment as physical space is bigger. An inlined 20 / 25MOA scope rail negates this advantage. 44mm less bright than 50mm which less bright than 56mm objective.... Quality of glass and coating a makes a huge fifference, but from the same maker / the same product range, bigger objective size = brighter image. Hope this helps.. Quote Link to comment Share on other sites More sharing options...
Gully Posted June 25, 2009 Author Report Share Posted June 25, 2009 Thanks, as I thought. So, if this is the case, why do S&B offer their scopes in both sizes? With about £40 difference between them. I keep seeing second hand 8x56's in 25mm and nearly buy them but hold back thinking I'll end up hating it and wanting the 30mm tube (i'm fickle!) Quote Link to comment Share on other sites More sharing options...
Baldrick Posted June 25, 2009 Report Share Posted June 25, 2009 It's the Americans that perpetuate the production of 1" tubes. The Europeans have been using 30mm tubes for decades. 30mm and 34mm are the way ahead. Quote Link to comment Share on other sites More sharing options...
Gully Posted June 25, 2009 Author Report Share Posted June 25, 2009 Cheers. 34mm eh??? Quote Link to comment Share on other sites More sharing options...
Westcountryman Posted June 25, 2009 Report Share Posted June 25, 2009 Not much difference, but if you have a really good set of mounts, in size X, you can get a S & B scope to match them. Quote Link to comment Share on other sites More sharing options...
Baldrick Posted June 25, 2009 Report Share Posted June 25, 2009 Cheers. 34mm eh??? Yes, and beyond (US Optics and IOR make tubes from 34-45mm, if I recall correctly). Weight becomes a significant issue above 30mm though - just pick up an S&B PMII, for instance. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.