Forgot Password
Pentax Camera Forums Home
Log in or register to remove ads.

Third-Party Pentax Lenses - Reviews and Database » Tamron Adaptall Lenses » Prime Lenses
Tamron Adaptall 105mm f/2.5 (CT-105) Review RSS Feed

Tamron Adaptall 105mm f/2.5 (CT-105)

Reviews Views Date of last review
4 42,877 Wed October 11, 2017
Recommended By Average Price Average User Rating
100% of reviewers $170.00 9.75
Tamron Adaptall 105mm f/2.5 (CT-105)

A relatively fast 105mm lens.
The earliest version is derived directly from the adaptamatic 105mm. It is very similar in specs and looks, but while the ct105 has all white lettering on the nameplate, on the early version "tamron" and " bbar multi c" are in green.

Focal Length (mm) 105
Aperture Maximum 2.5
Aperture Minimum 22
Optical Construction (elements / groups) 4/4
Minimum Focus Distance (mm from film plane) 1300
Filter Diameter (mm) 52
Length (mm at infinity) 52
Maximum Diameter (mm) 64.5
Weight (g) 275

Like all 1st gen adaptalls, this has a M42 style A-M (auto-manual) aperture switch. When using this lens with PK-M mount in manual (green button), or with PK-A mount in aperture priority (Av) mode, make sure this is set to "A". To use Av mode with PK-M mount, set to "M" (flick to "M" to stop down at the moment of taking the picture).
Mount Type: Third-party (adapter required)
Price History:

Add Review of Tamron Adaptall 105mm f/2.5 (CT-105)
Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-4 of 4

Registered: October, 2009
Location: Winchester
Posts: 2,523
Lens Review Date: October 11, 2017 I can recommend this lens: Yes | Price: None indicated | Rating: 9 

Pros: Smooth focusing, fast, sharp
Cons: Chromatic Aberations (red/green)
Sharpness: 9    Aberrations: 7    Bokeh: 9    Handling: 9    Value: 10    Camera Used: K1   

This is my Tamron from the 1970's, originally used on a Canon AE-1 (with FD mount) I got a KA mount for it some ago....didn't find much use for it on my K5 or K3, but if is a joy to use with my K1. Quite substantial in construction, and compact, this lens has a smooth focus action, and also nice buttery bokeh wide open. It is pretty sharp but does suffer from red/green CA. Usable at f2.5, I find 105mm to be a useful medium telephoto. I use a rubber lens hood but this does not seem to be too bad for flare. I can't remember how much I paid for it back in 1976(ish) but as it still works40 years later I am giving it 10/10 for value!

In Alresford box by Arle Images, on Flickr

In Alresford box by Arle Images, on Flickr
Junior Member

Registered: June, 2011
Location: N/A
Posts: 42
Lens Review Date: April 27, 2017 I can recommend this lens: Yes | Price: $190.00 | Rating: 10 

Pros: Light weight, sharp, fast
Cons: non
Sharpness: 10    Aberrations: 8    Bokeh: 10    Handling: 10    Value: 10   

I got lucky and found one of the first versions of the adaptall lenses, with the green "Tamron" on it. LOVE it! I'm using it on my K1, it's easy to focus, and has a beautiful bokeh.
New Member

Registered: January, 2012
Posts: 1
Lens Review Date: January 5, 2013 I can recommend this lens: Yes | Price: $150.00 | Rating: 10 

Pros: Sharpness, build quality, size and weight, bokeh.
Cons: None
Sharpness: 9    Aberrations: 8    Bokeh: 9    Handling: 9    Value: 10   

The lens is very well built, like all old lenses. Sharp enough already open aperture with a nice bokeh. Very soft and smooth focusing, the sharpness is very convenient. The lens has a small size and weight.
Before buying long chose between M 135 \ 3.5 and this lens, resulting in the selection of disappointed. I recommend this lens.
Here are the first test shots
Forum Member

Registered: February, 2011
Posts: 84

1 user found this helpful
Lens Review Date: September 13, 2011 I can recommend this lens: Yes | Price: None indicated | Rating: 10 

Pros: Sharp, good size, good feel of focusing ring
Cons: Just the photographer in my case
Sharpness: 9    Aberrations: 8    Bokeh: 9    Handling: 10    Value: 10   

Okay. Here's the thing. This lens literally fell from the sky and landed on my lap. Seriously. One day not too long ago I was horsing around in the office when the wife entered and said 'Oh I had totally forgotten I had this, here you go' and threw it on my lap.

Not having ever heard of it I put it on, went outside and took a few photos, wasn't anything spectacular - so I did what any reasonable person would have done, put it away. There it lived a good while.

Then one day I stumbled upon it again and took a few more photos and surprisingly they were not too shabby. Not too shabby at all, to be exact. Further investigation proved the piece is very nice in fact, and so much so that here's what my cat thought about it:


I'm afraid I did. In fact, here's a 100 % crop of the ear:

As you can see the lens does some pretty nice work there. Especially as the cat is a known ******* and generally refuses to stay still during a photo shoot, to which he's been subject to so often one would think the cat knew how to behave, but no, so the only logical conclusion is the before mentioned personality trait. Anyway. What we should all take away from this is that the lens is nice and that has in fact been taken at f/2.5 or full open (or almost, anyway), ISO 100, 1/180 w/flash and a K20D. Which is nice.

The lens seems to act a bit weird as the K20D lets me go to f/2.4.

Here's another one, again focused to ear, at f/2.4 (same settings as above):

This seems really pleasant, a tad softer than the other. I'm so going to use this lens for portraits.

As for f/11 I have - you guessed it - more cat pictures. Specifically, more cat ear pictures. And no, I don't have a thing for cat ears, I have a very annoying case of myopia and the Pentax diopter adjustment just won't fix it spot-on, so I tend to miss the focus without a split-screen focusing screen, which I relieved of duty a while back (see that review elsewhere on this site). But yeah, so deal with it.

The f/11 above is quite something. Also I seem to have suffered some brain hemorrhage, it's the only explanation for using the flash like that, just ignore it. Also note the ISO 400. Can't imagine why I did that.

The thing is, any model entering before this lens at f/11 damn well better have put on some makeup before showing up. I can't use these pictures! The cat's ear is too damn dirty! If it were a any sharper I think my eyes would bleed. Of joy.

The bokeh is also very nice, easy and steady blobs of awesome. Except when you start stopping it down, then it'll take a more uneasy direction, but nice all the same. For example, think of an ugly late september field. Just plain boring and dead. Except with the Tamron 105 f/2.5, it's not. It's shit like this:

That's at f/4.5, ISO 100, 1/1000 sec, K20D.

At f/2.5:

Consider that all you see above are unsharpened, unprocessed, just resized or cropped. Bite that, nifty fifty! Also, you're fired. Okay okay you're not - but still, the point stands.

Okay, it's not like everything's only perfect with this lens. I mean, one might maintain, that the aesthetic appeal is sub-optimal with this. The force may be with it, but hell, it looks just ugly. But that's just me, your own taste is of course your own fault.

Also the aberrations, they're ummh... definitely sometimes there.
Add Review of Tamron Adaptall 105mm f/2.5 (CT-105)

All times are GMT -7. The time now is 11:39 AM. | See also:, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]