# Thread: Angle of view - UWA

1. ## Angle of view - UWA

Dear All,

I have read the Wiki and some google results. So, I know what is Angle of view.

However, from my observation on the info from internet, I got the below list of angle of view from selected UWA:

Canon EF S10-22mm F3.5-4.5: 107°30’-63°30’ (http://www.canon.com.sg/section/digi...specs.jsp#zoom)
Sigma 10-20mm F4-5.6 EX DC HSM: 102.4 - 63.8 degrees (http://www.sigmaphoto.com/lenses/len...01&navigator=6)
Tokina 11-16mm F2.8 : 104°- 82° (http://www.tokinalens.com/products/t...16prodx-b.html)
Tokina 12-24mm F4: 99 - 61° (http://www.tokinalens.com/products/t...4prodx2-b.html)
Tamron SP AF10-24mm F/3.5-4.5: 108°44' - 60°20' (http://www.tamron.com/lenses/prod/1024_diII.asp)

Surprised me is the same focal length produced different angle (degrees), from different lens.

Calculation (Angular Field of View Calculator) from this website
http://www.tawbaware.com/maxlyons/calc.htm
indicating a
10 mm focal length on 1.6 crop will give diagonal degree of 107.
11 mm focal length on 1.6 crop will give diagonal degree of 101.7
12 mm focal length on 1.6 crop will give diagonal degree of 96.8

which is not same as what state in each of the above website.

Meanwhile,
10 mm focal length on 1.5 crop will give diagonal degree of 110.5
11 mm focal length on 1.5 crop will give diagonal degree of 105.3
12 mm focal length on 1.5 crop will give diagonal degree of 100.5

So my question: is it mean with Tokina 11-16 on 1.6 crop, you could capture wider scene compare to Sigma 10-20 on same sensor, even Tokina shorter by 1mm? Which info is more 'correct'? From the calculator, or from the manufacturer's website?

Thanks for those who enlighten me.

2. ## Re: Angle of view - UWA

it says the angle of view is applicable when SIGMA MOUNT IS USED. that has a crop factor of 1.7.

given SIMILAR CROP FACTOR, 10mm focal length lens is ALWAYS going to be wider than 11mm or 12mm. main thing is to convert to the SAME SCALE, which most commonly used is.. in 35mm (or full frame) terms.

3. ## Re: Angle of view - UWA

so in short, find out the focal length after crop factor, and then

use the angle of view calculator, that will give you the correct result, and it will be accurate.

4. ## Re: Angle of view - UWA

Originally Posted by night86mare

it says the angle of view is applicable when SIGMA MOUNT IS USED. that has a crop factor of 1.7.

given SIMILAR CROP FACTOR, 10mm focal length lens is ALWAYS going to be wider than 11mm or 12mm. main thing is to convert to the SAME SCALE, which most commonly used is.. in 35mm (or full frame) terms.
Ha ha, I just too busy look for other website, miss out the important 1st sentence. Thanks

5. ## Re: Angle of view - UWA

i am considering the following 3 lens but not sure which to get, please advice. Thank you

Canon EF S10-22mm F3.5-4.5
Tokina 11-16mm F2.8
Tamron SP AF10-24mm F/3.5-4.5

6. ## Re: Angle of view - UWA

Originally Posted by philozs
i am considering the following 3 lens but not sure which to get, please advice. Thank you

Canon EF S10-22mm F3.5-4.5
Tokina 11-16mm F2.8
Tamron SP AF10-24mm F/3.5-4.5
Please read up here, then maybe you can enlighten us a bit more. Mind-reading is not common here. Also, you might want to start new threads instead of digging up old threads that deal with a different question.
Things you might want to share with us: budget, camera (I guess a Canon crop factor, but also possible that you missed the point of EF-S), your current lens setup, your intentions for getting an UWA lens.

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