Green indicator on the 77mm?

**lithedreamer** · 01-26-2016, 11:23 AM

I've been loving the 77mm Limited (it convinced me to pick up the 43mm, too). However, I'm not sure why there's a big blue/green indicator on the lens. What is that for? None of the reviews seem to talk about it, and it isn't on any of my other lenses.

Adam · 01-26-2016, 11:32 AM - **1 Like**

Most legacy lenses have one too, though it's typically white or off white. It's used to help mount the lens. When the green dot is aligned with the lens release pin on the camera mount, you should be able to attach the lens without even looking at the red dots (i.e. while wearing the camera around your neck).

On DSLRs the lens release button is unfortunately pretty far below the pin itself, so this trick doesn't work as nicely as on film bodies.

stevebrot · 01-26-2016, 11:35 AM - **1 Like**

The "bump" or "nubbin" used to be a feature of ~~all~~ most* K-mount lenses, but disappeared with the DA and DFA series. On film cameras, it allows the photographer to mount a lens "eyes closed" by aligning the bump with the lens release on the body.

BTW, the bump on the FA Limiteds has a cloisonne enamel finish as one of their distinguishing features.

Steve

* Pancake and extremely compact lenses such as the FA 43/1.8 Limited don't have the bump.

**lithedreamer** · 01-26-2016, 11:35 AM

That makes so much sense Adam and Steve, thanks!

mikeSF · 01-26-2016, 02:45 PM

We luv the nub.

**monochrome** · 01-26-2016, 02:46 PM

Pretty little nubbin, isn't it?

bertwert · 01-26-2016, 02:47 PM

Ahh, that is what it is for. I've always wondered...

tgchan · 01-26-2016, 03:05 PM

You people have crushed my dream... I thought my limited has an emerald embedded in it...

**Digitalis** · 01-27-2016, 12:33 AM

Originally posted by tgchan

I thought my limited has an emerald embedded in it

no most lenses just have a piece of plastic, the FA limited lenses have an exotic form of Enamel Cloisonné.

**gofour3** · 01-27-2016, 11:48 AM

That little white/yellow/green bump on K-Mount lenses is actually called the "lens mounting guide bump" and was first introduced when the K Series was launched in June 1975.

The bump was used to assist in mounting a lens in low light, when you could not easily see the usual K-Mount red dots on the lens and camera body.

Here is an excerpt from the KX film camera manual on the usage:

Phil.

01-26-2016, 11:23 AM	#1
lithedreamer Site Supporter Join Date: Sep 2013 Photos: Gallery \| Albums Posts: 1,799	Green indicator on the 77mm? I've been loving the 77mm Limited (it convinced me to pick up the 43mm, too). However, I'm not sure why there's a big blue/green indicator on the lens. What is that for? None of the reviews seem to talk about it, and it isn't on any of my other lenses.

01-26-2016, 11:32 AM - 1 Like	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Most legacy lenses have one too, though it's typically white or off white. It's used to help mount the lens. When the green dot is aligned with the lens release pin on the camera mount, you should be able to attach the lens without even looking at the red dots (i.e. while wearing the camera around your neck). On DSLRs the lens release button is unfortunately pretty far below the pin itself, so this trick doesn't work as nicely as on film bodies. 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:

01-26-2016, 11:35 AM - 1 Like	#3
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	The "bump" or "nubbin" used to be a feature of ~~all~~ most* K-mount lenses, but disappeared with the DA and DFA series. On film cameras, it allows the photographer to mount a lens "eyes closed" by aligning the bump with the lens release on the body. BTW, the bump on the FA Limiteds has a cloisonne enamel finish as one of their distinguishing features. Steve * Pancake and extremely compact lenses such as the FA 43/1.8 Limited don't have the bump. Last edited by stevebrot; 01-26-2016 at 11:42 AM.

01-26-2016, 03:05 PM	#8
tgchan Senior Member Join Date: Jul 2014 Location: Poland, Radom Posts: 277	You people have crushed my dream... I thought my limited has an emerald embedded in it... Last edited by tgchan; 01-26-2016 at 03:19 PM.

01-27-2016, 11:48 AM	#10
gofour3 Site Supporter Join Date: Oct 2008 Location: Vancouver, Canada Posts: 8,091	That little white/yellow/green bump on K-Mount lenses is actually called the "lens mounting guide bump" and was first introduced when the K Series was launched in June 1975. The bump was used to assist in mounting a lens in low light, when you could not easily see the usual K-Mount red dots on the lens and camera body. Here is an excerpt from the KX film camera manual on the usage: Phil. Attached Images

01-26-2016, 11:35 AM	#4
lithedreamer Site Supporter Join Date: Sep 2013 Photos: Gallery \| Albums Posts: 1,799 Original Poster	That makes so much sense Adam and Steve, thanks!

01-26-2016, 02:45 PM	#5
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,620	We luv the nub.

01-26-2016, 02:46 PM	#6
monochrome Loyal Site Supporter Join Date: Mar 2008 Location: Working From Home Photos: Gallery \| Albums Posts: 26,276	Pretty little nubbin, isn't it?

01-26-2016, 02:47 PM	#7
bertwert Veteran Member Join Date: Jun 2015 Location: Golden, BC Posts: 15,173	Ahh, that is what it is for. I've always wondered...

01-27-2016, 12:33 AM	#9
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by tgchan I thought my limited has an emerald embedded in it no most lenses just have a piece of plastic, the FA limited lenses have an exotic form of Enamel Cloisonné.

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