Focus indicator dot with non AF-S lenses on d3100

[squirrels]

I'm using manual focus on a lens that won't autofocus on my d3100. I select my single focus point as if I were using autofocus. I focus as best I can and look for the little green light in the lower right corner to confirm that the camera also thinks I'm in focus. Am I just kidding myself with the little green dot or is this right?

C

 

[tagan]

Yeah, you can look for the little green dot when manual focusing. It will usually let you know when you have correct focus.

 

[squirrels]

Thanks! I thought it should work that way, but that doesn't always make it so.

C

 

[cgipson1]

That should work fine for you, squirrels.....

 

[KmH]

As an alternative, you can use Rangefinder mode. Page 144 of your D3100 users manual (the PDF file on the software disc).

The manual focus lens has to be a CPU lens with a D designation meaning the lens sends distance info to the camera., like AF 50 mm f/1.8D​

 

[squirrels]

Sweet. I will check that out. I'm obviously due up for another read through of the manual!

C

 

[squirrels]

Thanks Charlie! Oh my goodness you guys! Rangefinder mode is just way too much fun.:smileys:

 

[jrizal]

In case you have not noticed, rangefinder mode will not function in manual mode and only in aperture or shutter priority modes. Nonetheless, it is much easier to focus if it's on.

 

[amolitor]

I spend a lot of my life flipping between Manual and Av mode. The rangefinder works in Av, but the shutter won't release because the camera doesn't think there's a lens and anyway it can't meter. The shutter WILL release in manual.

 

[squirrels]

Yep. That's too bad about manual mode. I wish viewfinder had one of those cool split prism things my MILs old school film nikon camera has. Focusing on that bad boy was a piece of cake.

 

[squirrels]

Wait, so you have a "D" lens that works with the rangefinder but won't fire in anything but manual mode?

 

[amolitor]

Oh, no, sorry. I have a handful of AIS lenses. The camera actually insists that "No Lens Is Attached" with 'em.

 

[squirrels]

That is good to know! Thanks!

 

[snowbear121 52]

Yep. That's too bad about manual mode. I wish viewfinder had one of those cool split prism things my MILs old school film nikon camera has. Focusing on that bad boy was a piece of cake.

You mean one of these?
Nikon D3100 Focusing Screen - KatzEye Optics