Zoom stops

[Dirk Bouwen]

More a remark than a question...

It's a pity that the A1 doesn't have any straight forward reference to the zoom/focal stops.

It has a lens that in HD runs from focal distance 'SLR' equivalent of 32,5 to 650mm. It was almost by accident that I discovered under the 'custom functions', 'zoom indicator' you can switch from a dial to number indication. Doing this, a small calculation (assuming the lens behaves linear) leads to the following (I only retained the relevant 'photographic' numbers):

Number / focal d mm

0 32,5
3 51,22
11 101,14
17 138,58
27 200,98
43 300,82
59 400,66
91 600,34
99 650,26

This is surely of interest when you care about framing and the spacial look of your footage. Imagine that in photography it is hardly mainstream to walk around with anything above 200mm's... being in the A1 at about 1/3th of the zoom scale.

I also understand this won't be very accurate, but comparing it to a SLR, it should match to a certain extend. I've the impression it's a little bit more wide-angle in the lower numbers.

Anyone having thoughts on this?

[Chris Hurd]

Originally Posted by Dirk Bouwen

(assuming the lens behaves linear)

Well the focal length range is curvilinear, not rectilinear, so these values are not accurate, sorry.

I'll try to dig up the actual focal length values.

[Dirk Bouwen]

Thanks, Chris. I'm looking forward to this.

[Dirk Bouwen]

Originally Posted by Dirk Bouwen

More a remark than a question...

It's a pity that the A1 doesn't have any straight forward reference to the zoom/focal stops.

It has a lens that in HD runs from focal distance 'SLR' equivalent of 32,5 to 650mm. It was almost by accident that I discovered under the 'custom functions', 'zoom indicator' you can switch from a dial to number indication. Doing this, a small calculation (assuming the lens behaves linear) leads to the following (I only retained the relevant 'photographic' numbers):

Number / focal d mm

0 32,5
3 51,22
11 101,14
17 138,58
27 200,98
43 300,82
59 400,66
91 600,34
99 650,26

This is surely of interest when you care about framing and the spacial look of your footage. Imagine that in photography it is hardly mainstream to walk around with anything above 200mm's... being in the A1 at about 1/3th of the zoom scale.

I also understand this won't be very accurate, but comparing it to a SLR, it should match to a certain extend. I've the impression it's a little bit more wide-angle in the lower numbers.

Anyone having thoughts on this?

I revised the above with some measurements and calculations, and though I'm pretty sure it won't be mm-accurate, after a comparison with SLR it surely won't differ too much:

zoom reading / mm focal distance

0 33
5 40
10 45
20 50
40 75
60 125
75 180
90 350
95 500
99 650