Shipwreck Loc: Michigan

O.K., I have believed the size lens cover a lens uses is the same size as the lens (i.e. a 50 mm lens would have a 50 mm lens cover, for example). Today I was going to order some additional front (and rear) caps, blithely using my 50 mm cap for a 50 mm lens theory. Then I checked one of the covers already on a 24 - 50 mm lens. The size marked inside that lens cap is 62 mm. That kinda' blew my whole program. So, I have a 50 mm lens and 52 mm lens, each of which needs a lens cap........what size do I order?????? Yeah, yeah, I know I could measure the lens diameter, but there must be some sort of rule of thumb for this sort of thing. Obviously, the rear caps depend on the camera and its mounting.

Neal

marki3rd Loc: Columbus, Indiana

Well, you are correct about the rear cover having to be the correct one for the camera mount, but there is no way to say what front cover you need for either of your lenses without knowing exactly what lens it is for. The size of the front cover depends entirely on the diameter of the filter ring on the front of the lens (this also applies to the size of any filter you want to mount on the lens).

You mention that the cover for another lens you have is marked inside the cover with 62mm. What focal length is that lens?

If you can't make a reliable measurement of the lenses filter ring diameter, you might get a definitive answer if you post the model and mfg. of the lenses. BTW, some lenses have that measurement specified on the ID ring of the lens, but not all do.

speters Loc: Grangeville/Idaho

The lens's focal length has nothing to do with its filter size, the filter thread size is usually printed or engraved right one the front of the lens (when you look at it from the front), or you can look it up on the spec sheet.

Kuzano

The focal length of your lens (50mm, or 24-55) has nothing to do with your lens cap. The thread diameter of a lens cap is the front thread diameter of your lens, a specific thread diameter NOT dependent on the lens focal length. One way to get that diameter is to look on the inner side of a previous lens cap, or a thread diameter on a filter that fits. Sorry, it's just not that simple. Now you can get a ruler measure in mm (or centimeters marked off in tenths) and measure across the distance of the lens threads on the front of the lens, but that is a relatively crude measurement and would have to be refined by fitting a lens filter or cap on the actual front of the lens itself. They run the gamut of dimension and are rarely subject to the logic you are attempting to use.

In fact, using screw on caps, pinch on caps, and filter rings are so vastly different, that whole lens filter systems are sold so that you can put a filter holder on a variety of different lenses with an adaptor, and then use square filters at two inches or 2.5 inches and slide them on in front of any lens you use the system on.

Take your camera to a camera store that has a bunch of different size lens caps or screw on filters and get that dimension. Some lenses have it printed near the filter threads, but that's not dependable any more.

ggttc Loc: TN

Just go to Amazon and look up lens covers for your lens

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

Most lenses have something that looks like this Ø50mm printed on or near the front of the lens. This is the filter diameter/cap size.

SharpShooter Loc: NorCal

Neal, I couldn't find a cap for my 600mm lens, but the largest Cadallac hubcap I could find fit perfectly!! LoL
Actually you're gonna find that most manufactures try to share the same cap size over as many lens sizes as they can. For example on Canons the 77mm is the most common and the big super teles don't even have a real lens cap in the traditional sense!
SS

Rongnongno Loc: FL

Simply put:
The lens cover to select is equal to the filter diameter. It has nothing to do with the focal length. Not sure where you got that weird idea.

GoofyNewfie Loc: Kansas City

Not hard to find mis-information on the internet.

f8lee Loc: New Mexico

No kidding...I remember a few years back where it was tough to convince some folks that f-stop is not calculated based on focal length and diameter of the front elect of the lens.

Though I'll admit thesis the first time I've heard something like this. Just using common sense would seem to correct oneself - after all, how large is the lens cap on a 1000 MM lens? Certainly less than a meter!

Leitz Loc: Solms

The lens cap size will be the same as the lens' filter threads. This may be noted on the lens, in the user's guide that came with the lens, on the manufacturer's web page or, if discontinued, do a Google search for the specifications of your particular lens. I know of one 50mm lens that takes 34mm filters, another takes 67mm filters.

Shipwreck Loc: Michigan

Thanks, all, for your replies. My lens system is all Nikon, some have the filter diameter on them. Some don't. At any rate, I have measured them and have the problem all resolved. Again, thanks.
Neal

SharpShooter Loc: NorCal

Bob, see....., you have just proved your own theory!!!
You have no idea how big the lens cap on a 1000mm lens is, so you just guessed!!!
Now some poor little newbie is gonna read what you wrote and parrot that all over the Internet. That's how this missimfomation starts.
Do 1000mm lenses even have lens caps or filter treads?!?!

SS

Shipwreck Loc: Michigan

My 1000 mm lens doesn't have a lens cap. It has wheel lug studs and I just bolt on a Hummer wheel to protect the glass.
Neal

(I think I'm sorry I even brought my the lens cap situation......)

speters Loc: Grangeville/Idaho

My latest purchase, a 55mm/3.5 Takumar takes 100mm filters!