Bozsik Loc: Orangevale, California

I have mine on the front of my lens all the time, but I use this as a go-between. There are magnetic rings that make it easier to change filters. I have a lens cap on the front of the filter. When I don't need the CPL, I remove the cap and filter as one unit, otherwise I just remove the lens cap and the CPL is there. Check it out. It saves me a lot of time when I am using ND filters in landscape shots.
http://www.xumeadapters.com/

The only issue I have with them, but it isn't a concern if you don't have a really wide angle lens, is that you might get a small vignetting in the corners with very wide lenses. You should be good with the 28-300.

forjava Loc: Half Moon Bay, CA

Would be interested to know the names of some of the lenses, thanks. "older super multicoated lenses which give much more contrasty and saturated images than most modern lenses."

bimmer124 Loc: Woodstock, New York

I use Zeiss Icon.

philo Loc: philo, ca

I had a friend that left his on all the time. when i told him that he was losing 2 f stops he said he didn't give a damm. I quit telling him anything.

creativ simon Loc: Coulsdon, South London

No

TonyP Loc: New Zealand

Maybe because one doesn't always lose two stops?
Did an experiment yesterday, prompted by this thread, and because I do leave mine on most of the time.
You can lose up to two stops, but it depends on the angle to the light source.
With the CPL dialled right back and in hazy winter light there is no discernible loss. In the same light with the source exactly 90 degrees to my left the diff is probably just under two stops.
3 hours later, the sun came out so another play and yes, 2 stop difference between sun at right angles with full CPL (darkest) setting and lowest CPL setting and sun low in the sky and directly behind the camera.
Took the CPL off the camera, shot with the sun behind me and difference was about 1/2 a stop.
I realise this is just approximate as was only playing with the camera and didn't download pics to measure diffs on the computer.
The only time I take mine off is if I'm going to use a flash or I can't get a decent exposure inside.

anotherview Loc: California

You prove the obvious point that a careful photographer will consider the circumstances of his environment when doing photography and pertinent variables.

lamiaceae Loc: San Luis Obispo County, CA

Pentax! Especially the old Takumar ones. smc-Pentax is kind of a moniker if not trademark. But other brands like Nikon, Canon, Minolta, Olympus, etc., all made film lenses during the more or less 1970-1990 period with super coated lenses. They look very dark when viewed at oblique angles with crazy colored ghosts highlight reflections when view from the front looking in. Today's lenses look practically clear non-colored like those from the early 1950's and before. I did not expect anyone to take my comment as me knowing some secret. It is common knowledge to anyone doing photography for over 25 years. And not brand or model specific. Though single coated lenses throughout like filters were produced too as various model lenses as well. The coating has more to due with contrast and avoidance of flare than say sharpness per se. So not all lens formulas by every manufacturer came as these multiple coated lenses. I've heard that some really old timers prefer even today to use ancient un-coated view camera lenses to get deeper and more detailed blacks. But that can probably be achieved with PP these days. I've used vintage un-coated Goertz and Schneider large format lenses with no problems.

Robeng Loc: California

I travel Europe numerous times using a Nikon body with a 28mm-300mm lens. Good combo. As far as the filter goes just take it off when you don't need it.
Not a big deal.

lamiaceae Loc: San Luis Obispo County, CA

Further, this is kinda like those who have only owned cars less than say 20 years old and so they might not know that for older American automobiles typically you turned the Brights (secondary High Beam Headlights) on with a foot button switch in the upper left side of the foot area of the drivers side of many cars. Or what a hand choke was on a <1960 Car. Interesting but not essential to know as you will likely never have to deal with it. And so Photo Equipment if you don't plan on using vintage equipment (likely no AF or even EA). There are lots of things from the film days that are nearly forgotten or never learned by the only ever digital photographer. Some can still be useful (trivia or tricks). The Sunny Sixteen Rule, how to estimate the minimum shutter speed when hand holding a camera. I know a trick for calculating bellows extension for a view camera using a yard stick (or metal tape measure).

Frank47 Loc: West coast Florida

No. &#128247;

rgrenaderphoto Loc: Hollywood, CA

OK, you can be a purist, but from personal experience, breaking a Skylight or CEP filter on the front of the lens is far less expensive than the cost of a replacement lens or lens repair.

sterrill Loc: missouri

i use mine a lot especially for scenery. for inside pictures and with flash i tend to leave it off. i suggest leaving it on your d4 and getting a d5 for your other shots. just kidding of course.

Zone-System-Grandpa Loc: Springfield, Ohio

+++++++++++++++++++++++++++++++++++++

If your main objective is to protect your lens, forget a filter and keep your lens cap on the lens when not taking photographs. Keep filters off your lens if you can because they degrade your images, that is, unless you have high quality filters made by B+W or Zeiss. Even then, you are better off without a filter, unless you have some special effect that you are trying to get or should you need to reduce light intensity with a neutral density filter.

DerBiermeister Loc: North of Richmond VA

Is this from Tiffen purely hype?

"A Digital Ultra Clear is probably one of the most popular filters people use. As a lens protector, it should be left on at all times to guard against front element damage but also adds the benefit of rendering your images clearer.

The Digital Ultra Clear differs from Tiffen's standard UV filter in that it made with higher quality Water White glass that is optically purer. This kind of glass represents Tiffen's highest caliber of glass. Water White glass, using Tiffen’s ColorCore technology, is characterized by a high transmission quality. Typically, it will transmit 98-99% of the light. It also features an anti-glare and anti-reflective quality that makes it useful in a wide range of uses including the movie theater industry, store and art displays. The glass is virtually defect-free and is becoming more and more prevalent in digital equipment."