Screw on Lens Caps?

bobore · 11-01-2017, 01:19 AM

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Starting buying metal Japanese screw-on lens caps back in the '80s, and they're all I use.

Like the way they feel, look, and protect.

35mmfilmfan · 11-01-2017, 05:13 AM

Just found this on eBay - any suitable ?

pentax pka lens cap | eBay

timw4mail · 11-01-2017, 05:46 AM

Originally posted by bdery

My thought exactly. I'd rather have a plastic, clipped lens cap which can either shatter or jump out, taking some of the shock's energy with it along the way.

It's the same with modern cars : they're meant to absorb energy so you don't have to.

Somehow I doubt there's that much engineering to lens caps... just that plastic absorbs energy better than metal.

**csa** · 11-02-2017, 08:32 AM

Originally posted by UncleVanya

I replaced my da 15 hood as soon as possible with a pinch cap. The speed of putting screw on caps on and off is either too much of a pain and the cap says off longer than normal, or an impediment to a quick shot, or both.

I agree, I do not like the screw on caps! I've gone to the lens Hood Hats from OpTech for most of my lenses, & prefer them to even the pinch caps.

Hood Hat - Lens Cover | OP/TECH USA

Parallax · 11-02-2017, 08:43 AM

Originally posted by Adam

Wouldn't those screw-in caps be more likely to dent or damage the filter threads if impacted from the front?

It would make them less vulnerable as the impact force would be distributed over the entirety of the threads rather than a single point or small area.
You can demonstrate this by striking a bare bolt on the end with a hammer and look at the thread damage. Now try the same thing with another one with a nut screwed on covering the threads.

**UncleVanya** · 11-02-2017, 10:09 AM

Originally posted by Parallax

It would make them less vulnerable as the impact force would be distributed over the entirety of the threads rather than a single point or small area.
You can demonstrate this by striking a bare bolt on the end with a hammer and look at the thread damage. Now try the same thing with another one with a nut screwed on covering the threads.

That doesn't seem like a similar comparison. The lens threads area is a hollow section unlike the bolt. The problem Adam is talking likely has to do with the elastic vs. inelastic collision that may occur - how much the lens bounces off and how much energy is absorbed by the cap breaking or dislodging vs. how much energy is retained in the collision. I would think a metal screw in cap has a higher chance for an inelastic collision.

---------- Post added 11-02-17 at 01:10 PM ----------

Originally posted by csa

I agree, I do not like the screw on caps! I've gone to the lens Hood Hats from OpTech for most of my lenses, & prefer them to even the pinch caps.

Hood Hat - Lens Cover | OP/TECH USA

Do you see any wear on the lens where these contact them?

**csa** · 11-02-2017, 10:27 AM

No, no wear visible at all. These are a very soft material, so unlikely they would wear the finish on lenses.

**UncleVanya** · 11-02-2017, 11:18 AM

Originally posted by csa

No, no wear visible at all. These are a very soft material, so unlikely they would wear the finish on lenses.

Even fingers and bags wear lenses bodies over time - so I was worried. But good to hear that they do not appear to do so.

Adam · 11-02-2017, 12:05 PM

Originally posted by UncleVanya

That doesn't seem like a similar comparison. The lens threads area is a hollow section unlike the bolt. The problem Adam is talking likely has to do with the elastic vs. inelastic collision that may occur - how much the lens bounces off and how much energy is absorbed by the cap breaking or dislodging vs. how much energy is retained in the collision. I would think a metal screw in cap has a higher chance for an inelastic collision.

Originally posted by Parallax

It would make them less vulnerable as the impact force would be distributed over the entirety of the threads rather than a single point or small area. You can demonstrate this by striking a bare bolt on the end with a hammer and look at the thread damage. Now try the same thing with another one with a nut screwed on covering the threads.

Yeah, what I'm thinking is if the cap gets hit and goes flying off (as would be the case with a plastic clip on cap), the force of the impact would be diverted away from the lens entirely as it bounces back from the collision.

**Digitalis** · 11-02-2017, 03:02 PM - **2 Likes**

Originally posted by UncleVanya

Even fingers and bags wear lenses bodies over time

**UncleVanya** · 11-02-2017, 03:06 PM

Badges of honor.

**csa** · 11-02-2017, 04:14 PM

Originally posted by UncleVanya

Even fingers and bags wear lenses bodies over time - so I was worried. But good to hear that they do not appear to do so.

This is just my experience so far. I'm not a "heavy hitter" photographer taking hundreds of shots a day, etc. But so far I've not seen any wear on any of my lenses.

**sibyrnes** · 11-02-2017, 05:55 PM

Originally posted by Adam

Yeah, what I'm thinking is if the cap gets hit and goes flying off (as would be the case with a plastic clip on cap), the force of the impact would be diverted away from the lens entirely as it bounces back from the collision.

That's not my experience. Fortunately I had a UV screw-on filter that shattered but still protected the lens. I'm confident that if I had a metal screw on lens cap installed I would have suffered no damage. But I also kind of like the look and feel - not trying to convince anyone else - just interested in opinions.

**Digitalis** · 11-03-2017, 12:02 AM

Originally posted by UncleVanya

Badges of honor.

Unless sandpaper is involved, which is tragically the case with pre-aged Leica cameras.

Originally posted by csa

This is just my experience so far. I'm not a "heavy hitter" photographer taking hundreds of shots a day, etc. But so far I've not seen any wear on any of my lenses.

My FA limited lenses are brassing up nicely. I don't mistreat my gear, but I don't coddle either.

**UncleVanya** · 11-03-2017, 05:49 AM

Originally posted by Digitalis

Unless sandpaper is involved, which is tragically the case with pre-aged Leica cameras.

WOW! What a tragedy.

11-02-2017, 12:05 PM	#24
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,597	Originally posted by UncleVanya That doesn't seem like a similar comparison. The lens threads area is a hollow section unlike the bolt. The problem Adam is talking likely has to do with the elastic vs. inelastic collision that may occur - how much the lens bounces off and how much energy is absorbed by the cap breaking or dislodging vs. how much energy is retained in the collision. I would think a metal screw in cap has a higher chance for an inelastic collision. Originally posted by Parallax It would make them less vulnerable as the impact force would be distributed over the entirety of the threads rather than a single point or small area. You can demonstrate this by striking a bare bolt on the end with a hammer and look at the thread damage. Now try the same thing with another one with a nut screwed on covering the threads. Yeah, what I'm thinking is if the cap gets hit and goes flying off (as would be the case with a plastic clip on cap), the force of the impact would be diverted away from the lens entirely as it bounces back from the collision. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

11-02-2017, 05:55 PM	#28
sibyrnes Site Supporter Join Date: May 2016 Location: Pittsburgh, Pa. Photos: Gallery \| Albums Posts: 447 Original Poster	Originally posted by Adam Yeah, what I'm thinking is if the cap gets hit and goes flying off (as would be the case with a plastic clip on cap), the force of the impact would be diverted away from the lens entirely as it bounces back from the collision. That's not my experience. Fortunately I had a UV screw-on filter that shattered but still protected the lens. I'm confident that if I had a metal screw on lens cap installed I would have suffered no damage. But I also kind of like the look and feel - not trying to convince anyone else - just interested in opinions. Last edited by sibyrnes; 11-02-2017 at 06:00 PM.

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11-01-2017, 01:19 AM	#16
bobore Senior Member Join Date: Oct 2009 Location: North Oregon Coast Posts: 162	Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. Starting buying metal Japanese screw-on lens caps back in the '80s, and they're all I use. Like the way they feel, look, and protect.

11-01-2017, 05:13 AM	#17
35mmfilmfan Pentaxian Join Date: Oct 2016 Location: Norfolk, UK Posts: 4,336	Just found this on eBay - any suitable ? pentax pka lens cap \| eBay

11-01-2017, 05:46 AM	#18
timw4mail Pentaxian Join Date: Apr 2017 Location: Driving a Mirage Photos: Gallery \| Albums Posts: 1,670	Originally posted by bdery My thought exactly. I'd rather have a plastic, clipped lens cap which can either shatter or jump out, taking some of the shock's energy with it along the way. It's the same with modern cars : they're meant to absorb energy so you don't have to. Somehow I doubt there's that much engineering to lens caps... just that plastic absorbs energy better than metal.

11-02-2017, 08:32 AM	#19
csa Loyal Site Supporter Join Date: Aug 2014 Location: Montana mountains Posts: 10,133	Originally posted by UncleVanya I replaced my da 15 hood as soon as possible with a pinch cap. The speed of putting screw on caps on and off is either too much of a pain and the cap says off longer than normal, or an impediment to a quick shot, or both. I agree, I do not like the screw on caps! I've gone to the lens Hood Hats from OpTech for most of my lenses, & prefer them to even the pinch caps. Hood Hat - Lens Cover \| OP/TECH USA

11-02-2017, 08:43 AM	#20
Parallax Senior Moderator Loyal Site Supporter Join Date: Apr 2008 Location: South Dakota Photos: Gallery Posts: 19,332	Originally posted by Adam Wouldn't those screw-in caps be more likely to dent or damage the filter threads if impacted from the front? It would make them less vulnerable as the impact force would be distributed over the entirety of the threads rather than a single point or small area. You can demonstrate this by striking a bare bolt on the end with a hammer and look at the thread damage. Now try the same thing with another one with a nut screwed on covering the threads.

11-02-2017, 10:09 AM	#21
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Originally posted by Parallax It would make them less vulnerable as the impact force would be distributed over the entirety of the threads rather than a single point or small area. You can demonstrate this by striking a bare bolt on the end with a hammer and look at the thread damage. Now try the same thing with another one with a nut screwed on covering the threads. That doesn't seem like a similar comparison. The lens threads area is a hollow section unlike the bolt. The problem Adam is talking likely has to do with the elastic vs. inelastic collision that may occur - how much the lens bounces off and how much energy is absorbed by the cap breaking or dislodging vs. how much energy is retained in the collision. I would think a metal screw in cap has a higher chance for an inelastic collision. ---------- Post added 11-02-17 at 01:10 PM ---------- Originally posted by csa I agree, I do not like the screw on caps! I've gone to the lens Hood Hats from OpTech for most of my lenses, & prefer them to even the pinch caps. Hood Hat - Lens Cover \| OP/TECH USA Do you see any wear on the lens where these contact them?

11-02-2017, 10:27 AM	#22
csa Loyal Site Supporter Join Date: Aug 2014 Location: Montana mountains Posts: 10,133	No, no wear visible at all. These are a very soft material, so unlikely they would wear the finish on lenses.

11-02-2017, 11:18 AM	#23
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Originally posted by csa No, no wear visible at all. These are a very soft material, so unlikely they would wear the finish on lenses. Even fingers and bags wear lenses bodies over time - so I was worried. But good to hear that they do not appear to do so.

11-02-2017, 03:02 PM - 2 Likes	#25
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by UncleVanya Even fingers and bags wear lenses bodies over time

11-02-2017, 03:06 PM	#26
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Badges of honor.

11-02-2017, 04:14 PM	#27
csa Loyal Site Supporter Join Date: Aug 2014 Location: Montana mountains Posts: 10,133	Originally posted by UncleVanya Even fingers and bags wear lenses bodies over time - so I was worried. But good to hear that they do not appear to do so. This is just my experience so far. I'm not a "heavy hitter" photographer taking hundreds of shots a day, etc. But so far I've not seen any wear on any of my lenses.

11-03-2017, 12:02 AM	#29
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by UncleVanya Badges of honor. Unless sandpaper is involved, which is tragically the case with pre-aged Leica cameras. Originally posted by csa This is just my experience so far. I'm not a "heavy hitter" photographer taking hundreds of shots a day, etc. But so far I've not seen any wear on any of my lenses. My FA limited lenses are brassing up nicely. I don't mistreat my gear, but I don't coddle either.

11-03-2017, 05:49 AM	#30
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Originally posted by Digitalis Unless sandpaper is involved, which is tragically the case with pre-aged Leica cameras. WOW! What a tragedy.