An other telelens comparison : Pentax vs. Takumar vs. Tamron

CarbonR · 12-15-2020, 01:59 PM

I was not exactly expecting this :
- Tamron is better than I had in mind (I had one in the past)... but to focus with it is like sitting on a cactus, the focusing ring is too much reactive.
- The Takumar 400/4 is better than the 500/4.5, this does meet my feeling.... but I was waiting is at a better general level.
- I am still having trouble to do a 100% good focus, I need to develop something to do it more acurately.

**GUB** · 12-15-2020, 02:53 PM

Originally posted by CarbonR

- I am still having trouble to do a 100% good focus, I need to develop something to do it more acurately.

That is why I have a target fore and aft of the main target. If they are both equally blurred then you have nailed it.

**pentaxus** · 12-15-2020, 10:21 PM

Back and forth focusing is the historically recommended way to manually focus. It is just time consuming and difficult with moving objects.

CarbonR · 12-15-2020, 11:15 PM - **1 Like**

Originally posted by GUB

That is why I have a target fore and aft of the main target. If they are both equally blurred then you have nailed it.

I'll use a better way (to my opinion) : a sort of ruler at 45°. No need to compare front and rear caps, juste to see where the focus is

Originally posted by pentaxus

Back and forth focusing is the historically recommended way to manually focus. It is just time consuming and difficult with moving objects.

This is what I always do but with a thin DOF and some lenses having not extremely precise focusing ring, this is tricky to achieve the right focus, especially in lieview x10 on a 300-400mm.

I will do an other test because I want to see how the Tamron handles with a 2X converter.

LensBeginner · 12-16-2020, 01:11 AM - **1 Like**

Very nice job, just like your last one

GUB
Technically not equally blurred, if they are at the same distance. If the back one is (roughly) two times further than the closest one, then yes

pentaxus
Yup, been there, done that

**GUB** · 12-16-2020, 02:33 AM

Originally posted by CarbonR

I'll use a better way (to my opinion) : a sort of ruler at 45°. No need to compare front and rear caps, juste to see where the focus is

Yep that is the best way.
I use the caps @ 100x the focal length away as a standardised approach. Anyone with those caps can replicate the comparison if they want.

Originally posted by LensBeginner

GUB
Technically not equally blurred, if they are at the same distance. If the back one is (roughly) two times further than the closest one, then yes

Yeah naaa I mean it as a rough and ready indicator. I have them about 400 - 500 away from the centre one.

**DWS1** · 12-16-2020, 05:58 PM

I appreciate your time and effort. Thanks for sharing.

beachboy2 · 12-16-2020, 07:26 PM

The Tamron 60B works well with the Pentax-F SMC 1.7x AF adapter. Very fast and accurate auto focus as a 510mm f5.6.

12-15-2020, 01:59 PM	#1
CarbonR Pentaxian Join Date: Jul 2010 Location: Clermont-Ferrand, France Posts: 363	An other telelens comparison : Pentax vs. Takumar vs. Tamron I was not exactly expecting this : - Tamron is better than I had in mind (I had one in the past)... but to focus with it is like sitting on a cactus, the focusing ring is too much reactive. - The Takumar 400/4 is better than the 500/4.5, this does meet my feeling.... but I was waiting is at a better general level. - I am still having trouble to do a 100% good focus, I need to develop something to do it more acurately.

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12-15-2020, 02:53 PM	#2
GUB Loyal Site Supporter Join Date: Aug 2012 Location: Wanganui Photos: Gallery \| Albums Posts: 5,760	Originally posted by CarbonR - I am still having trouble to do a 100% good focus, I need to develop something to do it more acurately. That is why I have a target fore and aft of the main target. If they are both equally blurred then you have nailed it.

12-15-2020, 10:21 PM	#3
pentaxus Site Supporter Join Date: Jun 2010 Location: Central Coast, CA Posts: 1,313	Back and forth focusing is the historically recommended way to manually focus. It is just time consuming and difficult with moving objects.

12-15-2020, 11:15 PM - 1 Like	#4
CarbonR Pentaxian Join Date: Jul 2010 Location: Clermont-Ferrand, France Posts: 363 Original Poster	Originally posted by GUB That is why I have a target fore and aft of the main target. If they are both equally blurred then you have nailed it. I'll use a better way (to my opinion) : a sort of ruler at 45°. No need to compare front and rear caps, juste to see where the focus is Originally posted by pentaxus Back and forth focusing is the historically recommended way to manually focus. It is just time consuming and difficult with moving objects. This is what I always do but with a thin DOF and some lenses having not extremely precise focusing ring, this is tricky to achieve the right focus, especially in lieview x10 on a 300-400mm. I will do an other test because I want to see how the Tamron handles with a 2X converter.

12-16-2020, 01:11 AM - 1 Like	#5
LensBeginner Veteran Member Join Date: Sep 2014 Photos: Albums Posts: 4,696	Very nice job, just like your last one GUB Technically not equally blurred, if they are at the same distance. If the back one is (roughly) two times further than the closest one, then yes pentaxus Yup, been there, done that

12-16-2020, 02:33 AM	#6
GUB Loyal Site Supporter Join Date: Aug 2012 Location: Wanganui Photos: Gallery \| Albums Posts: 5,760	Originally posted by CarbonR I'll use a better way (to my opinion) : a sort of ruler at 45°. No need to compare front and rear caps, juste to see where the focus is Yep that is the best way. I use the caps @ 100x the focal length away as a standardised approach. Anyone with those caps can replicate the comparison if they want. Originally posted by LensBeginner GUB Technically not equally blurred, if they are at the same distance. If the back one is (roughly) two times further than the closest one, then yes Yeah naaa I mean it as a rough and ready indicator. I have them about 400 - 500 away from the centre one.

12-16-2020, 05:58 PM	#7
DWS1 Site Supporter Join Date: Aug 2018 Location: Arkansas, USA Posts: 1,169	I appreciate your time and effort. Thanks for sharing.

12-16-2020, 07:26 PM	#8
beachboy2 Senior Member Join Date: Dec 2012 Location: Perth Western Australia Photos: Gallery Posts: 222	The Tamron 60B works well with the Pentax-F SMC 1.7x AF adapter. Very fast and accurate auto focus as a 510mm f5.6.