Darren, while I certainly understand your aversion to using filters as lens front element protectors, my own experience leads me to disagree with your conclusions.
First of all, I don’t believe high quality filters will appreciably degrade the quality of images produced by high quality lenses. The far greater and more common degrades come from misfocus, and camera movement during exposure, and poor exposure in the first place. I do believe the filter should be used in conjunction with a lens shade to minimize the aggravation of flare problems.
I actually have seen horribly mangled front lens elements – scratched, dinged, gouged, smeared, etc. that I would think should make it impossible to shoot a decent image but that actually produce very good images, under ideal conditions. They do poorly, though, when the conditions are in any way likely to generate flare. A lens with pristine front element but fitted with a dirty, scratched, gouged, etc. filter will perform similarly.
Second of all, I think it is fairly easy to damage a lens front element. I have seen numerous high-end lenses badly compromised by damaged front lens elements that were not protected by filters. I have in mind, especially, 9 separate lenses worth in aggregate about $12,500 (street price) used by colleagues over the last 4-5 years. These lenses have been in daily service under all kinds of ordinary (but no extreme) weather and shooting conditions.
I’ll acknowledge the damage has been due, mainly, to careless handling. But it doesn’t take much to do the damage – a little junk in the bottom of a camera bag has done the worst damage to front elements in almost every case. Optical glass and coatings are relatively soft and easy to mar. The repairs – to replace damaged front lens elements – run considerably higher in cost (and take a lot longer) than replacing a protective filter.
Yes, the damaged lenses are used by professionals, and they are not protected by filters. They are “company” gear, and not personal equipment. Most pro shooters I know who use their own gear do protect investment and livelihood by covering the front elements of their own lenses with filters and protecting them with shades.
Not long ago I watched one colleague heave a huge sigh of relief when he realized the damage done by foul tipped softball that hit the front of his 70-200mm lens was a demolished lens hood and clear filter; the front element of the lens was clean as a whistle.
I do note that some of the lens shades these days provide little physical protection, and do not fasten onto the lens very securely. That can be a problem, in my opinion.
Third, there is a reason most of the “big glass” lenses – the super fast, long FL lenses -- have “sacrificial” front elements. These are designed to be readily replaced at relatively low cost (several hundred bucks, I believe), compared to cost of the lens itself. They are out there, and vulnerable to degrading damage.
Fourth, protecting the rear elements of your lenses is crucial. I have had more trouble with image degrade due to marked or smudged rear lens elements than with front elements.
Now, here’s how my own lenses actually get used, every day.
1) Each lens is equipped with a good quality “clear” filter to protect its front element.
2) Filters are cleaned, as needed. The lens glass is very rarely touched (not necessary).
3) Each lens is fitted with its own shade.
4) Dismounted lenses are carried in a camera gear bag that has padded compartments.
5) I rarely use front lens caps.
6) I do use rear lens caps on dismounted lenses.
7) I do not “stack” filters.
When hiking, dismounted lenses are carried in Neoprene pouches, just as they are carried in the camera gear bag for daily use.
G.
I just ordered the B+W F-PRO MRC circular polarizer for the 50mm. It'll be awhile before I can afford the 2nd lens so the 50mm will be my mountain lens for now. Thanks for the clarification. You make some valid points.
