[LennyBloke]

Dustin Abot said that it would be good if Tamron added a focus limiter, Ricoh did it on the Pentax version, which is a good thing

Some of Tamron 70-210 reviews say that the lens AF hunts when at 210mm with a close subject. Did you test the lens for that specific AF condition?

I didn't test for AF hunting specifically at 210mm - but judging by my LR catalog more than half of the shots I took were at that length and I certainly didn't notice hunting at the time of shooting. I've used it a fair amount since and the only thing I have noticed is the occasional refusal to shoot (due to non-locked focus) when following a moving subject - but I don't believe this is specific to this lens!

I will look out for close-focus hunting at 210 over the next few days - we have some blossom in its early stages that may suit pseudo-macro, that should test it

[biz-engineer]

I didn't test for AF hunting specifically at 210mm - but judging by my LR catalog more than half of the shots I took were at that length and I certainly didn't notice hunting at the time of shooting.

I see. Looking at the Tamron again, it seems AF issues occured early when the product was released, then Tamron release a lens firmware update that fixed the AF issue. So obviously the Pentax DFA70-210 got the new firmware before release in 2020.

[Sandy Hancock]

Has anyone already noticed that 70-210 x 1.4 x 1.53 = 150-450? Like almost exactly?

Coincidence?

[SSGGeezer]

Has anyone already noticed that 70-210 x 1.4 x 1.53 = 150-450? Like almost exactly?

Coincidence?

Where is the magical 1.53 coming from Sandy? Have you been in the ether again?

[normhead]

Crop factor advantage?

[Sandy Hancock]

Where is the magical 1.53 coming from Sandy?

1.53 is the precise crop factor from 36x24 to APS-C. I thought everyone knew that
1.4 is the teleconverter.

So, if you put the DFA 70-210 on a crop camera with the teleconverter, you have a more or less exact field of view equivalent to the DFA150-450 on full frame.

I just thought it was interesting.

[SSGGeezer]

1.53 is the precise crop factor from 36x24 to APS-C. I thought everyone knew that
1.4 is the teleconverter.

So, if you put the DFA 70-210 on a crop camera with the teleconverter, you have a more or less exact field of view equivalent to the DFA150-450 on full frame.

I just thought it was interesting.

I suspect I have heard/read that multiple times here in the forum it is just that I ignore the crop factor and all the equivalence talk since I see what I see in the OVF.
I was just going for the humor to the anesthesiologist! Failed!

[normhead]

1.53 is the precise crop factor from 36x24 to APS-C. I thought everyone knew that
1.4 is the teleconverter.

So, if you put the DFA 70-210 on a crop camera with the teleconverter, you have a more or less exact field of view equivalent to the DFA150-450 on full frame.

I just thought it was interesting.

But if you put the 150-450 on an APS-c crop you get 688. And if you put the 1.4 on the 150-450 you get 964.

I bought my Tammy 300 so I'd have the same as the 200 2.8 on my K-1. Then I discovered that the 1.4 for 420x 1.53 = 647mm (crop factor.)

The trouble is, no matter what you do that 1.53 is good on any lens.
The one exception being the Tamron 2x works pretty good on the K-1 but it's soft on the K-3. SO I can get to 647mm equivalent on the K-3 but 600mm on the K-1, and the K-1 will have better resolution.

So despite crop factor, the K-1 and Tamron 300 2.8 and Tamorn 2x TC gives me more reach than any APS_c combo I own.

Those are a few of the things you don't know if you don't own the gear.

Tamron 300 2.8 and Tamron 2x TC for 600mm on the K-1


Really, not too shabby

[luftfluss]

1.53 is the precise crop factor from 36x24 to APS-C. I thought everyone knew that
1.4 is the teleconverter.

So, if you put the DFA 70-210 on a crop camera with the teleconverter, you have a more or less exact field of view equivalent to the DFA150-450 on full frame.

I just thought it was interesting.

My K-01 has a crop factor of only 1.52x

Anyway, nice work with the numbers!

[mattt]

I put the 70-210 to work this past week and dropped a few more pics in that folder of mine

I shot the whole works wide open with flash and some changing natural light which presented challenges... and I got bit with moire (bad matt).

Anyway, we had fun and I put a couple bucks in my jeans to help with the cost of the new piece of kit.

[Sandy Hancock]

But if you put the 150-450 on an APS-c crop you get 688. And if you put the 1.4 on the 150-450 you get 964.

Thanks Norm. I'm not sure those numbers resonate with me.

I have the DFA150-450 as well. It's still my choice for extreme reach, and I use it on crop more than full frame.

I merely wanted to point out the interesting mathematical relationship between the two.

[monochrome]

Thanks Norm. I'm not sure those numbers resonate with me.

I have the DFA150-450 as well. It's still my choice for extreme reach, and I use it on crop more than full frame.

I merely wanted to point out the interesting mathematical relationship between the two.

I wonder if there was a Grand Vision or was this all just a big coincidence?

[Paul the Sunman]

I wonder if there was a Grand Vision or was this all just a big coincidence?

Pentax has long been renowned for its weird numbers: 31, 43, 77. Perhaps there is some deeper meaning.

[Sandy Hancock]

I wonder if there was a Grand Vision or was this all just a big coincidence?

My precise point.

[Sandy Hancock]

I was just going for the humor to the anesthesiologist!
Failed!

Indeed. You should know we have no sense of humour