Whats the different from CF and FF?

[night86mare]

anyways, there is a quick explanation for the 102 deg.

please see http://www.sigmaphoto.com/shop/10-20mm-f4-56-ex-dc-hsm-sigma#n1

please take note of the small little 1 subscript.

please click on it.

then please find out what the crop factor for sigma is. tada, problem solved. it is 1.7x.

http://dpanswers.com/content/tech_crop.php

wiki gives http://en.wikipedia.org/wiki/Angle_of_view

18mm as 100 deg diagonal FOV, so... that's the reason.

 

[kriegsketten]

no, focal length is not really representative of field of view.

10mm fisheye for example on DX lens will have a much wider FOV than a 10mm rectilinear lens.

so things like how well the distortion is corrected would also PROBABLY affect effective FOV.

that said, we can usually expect a 10mm lens to be wider than an 11mm lens, given that they are both rectilinear.

Exactly, but don't forget how each lens element is created - curvature of the surface etc...the light reflected off from one element to the next WILL be different if they are created differently between two lenses (whether both 10mm and rectilinear or not). Basic science...

 

[ZerocoolAstra]

no, focal length is not really representative of field of view.

10mm fisheye for example on DX lens will have a much wider FOV than a 10mm rectilinear lens.

so things like how well the distortion is corrected would also PROBABLY affect effective FOV.

that said, we can usually expect a 10mm lens to be wider than an 11mm lens, given that they are both rectilinear.

hmmmm you have a point...
damn this is too much for me...
brain is half asleep...

 

[kriegsketten]

anyways, there is a quick explanation for the 102 deg.

please see http://www.sigmaphoto.com/shop/10-20mm-f4-56-ex-dc-hsm-sigma#n1

please take note of the small little 1 subscript.

please click on it.

then please find out what the crop factor for sigma is. tada, problem solved. it is 1.7x.

http://dpanswers.com/content/tech_crop.php

wiki gives http://en.wikipedia.org/wiki/Angle_of_view

18mm as 100 deg diagonal FOV, so... that's the reason.

So what it is saying is, if you put that lens on a 1.5 crop body, the angle of view should equate to 109 deg? :think:

 

[kriegsketten]

You should try shooting with the Sigma 12-24 of FF. :angel:

Oh okay lolz owned! :bsmilie: Oh WOW, a whopping 122 degrees! Move over, Nikon 14-24mm!

 

[night86mare]

So what it is saying is, if you put that lens on a 1.5 crop body, the angle of view should equate to 109 deg? :think:

what it is saying is that sigma is idiotically listing FOV on its website as that of the lens on 1.7x crop body.

 

[kriegsketten]

what it is saying is that sigma is idiotically listing FOV on its website as that of the lens on 1.7x crop body.

Haiz... I see... But no leh, is it because it is to support Sigma's own Crop DSLR body?

*edit: Ah yes! The Sigma SD15 is a 1.7x crop sensor!!! CASE CLOSED... Nobody's falsifying ANYTHING!

 

[ZerocoolAstra]

phew... ~faint~

 

[wootsk]

no, focal length is not really representative of field of view.

10mm fisheye for example on DX lens will have a much wider FOV than a 10mm rectilinear lens.

so things like how well the distortion is corrected would also PROBABLY affect effective FOV.

that said, we can usually expect a 10mm lens to be wider than an 11mm lens, given that they are both rectilinear.

Aiya, just lean back a bit and you still see the covered area is the same.:bsmilie:

 

[kriegsketten]

Aiya, just lean back a bit and you still see the covered area is the same.:bsmilie:

So simple har?? It depends on the objects in the distance that you want to cover okay? The further the distance, the greater the differences - you'll need to do more than leaning back...maybe take a few steps onto the road of on-coming traffic if you're on the bridge's ledge... :bsmilie: I thought my math already fail, yours failed 1.5x over mine! lolz

 

[daredevil123]

Hmmmm so NNB's 16mm is 2 degress wider than my 11mm. But what I saw seems to so much more than 2degrees.

Nevermind. Tomorrow morning is our sunrise shoot. I will setup next to him and we do a shoot out again.

 

[ZerocoolAstra]

Hmmmm so NNB's 16mm is 2 degress wider than my 11mm. But what I saw seems to so much more than 2degrees.

Nevermind. Tomorrow morning is our sunrise shoot. I will setup next to him and we do a shoot out again.

For a 1 degree difference on either side of the perpendicular, the difference (@200m straight line distance) is 3.5m
[tangent (1 degree) x 200m]

So NNB is seeing 7m wider at a distance of 200m, and 7m taller. Quite a lot

 

[kriegsketten]

For a 1 degree difference on either side of the perpendicular, the difference (@200m straight line distance) is 3.5m
[tangent (1 degree) x 200m]

So NNB is seeing 7m wider at a distance of 200m, and 7m taller. Quite a lot

Whatever you do DD123, do not, I repeat DO NOT challenge his shots when you try to capture Battam Island on a clear day! You'll only get disappointed much much more! :bsmilie:

I think most peeps have the misconception of degree differences. True, 3 degrees may not be much when you shoot objects are close range. Eg. Group of people against a wall, 2 meters away (yeah, you can just lean back in this case). But the same 3 degrees will fan out to much greater differences against objects 100 km away! For the same scene, you can even notice the BIG change between just 1 deg difference. We use UWA for the great expanse of nature and city skylines, not normal day-to-day shoots, hence the crave for greater FOVs where 1 deg extra may make or break a photo composition if walking space is limited...

Whatever it is, ZCA has clearly illustrated the math in all this, maybe he will coach us during one of the outings?? :bsmilie:

 

[kriegsketten]

Hmmmm so NNB's 16mm is 2 degress wider than my 11mm. But what I saw seems to so much more than 2degrees.

Nevermind. Tomorrow morning is our sunrise shoot. I will setup next to him and we do a shoot out again.

2? 107 - 104 = 3 degrees, laddie... one extra deg makes a great difference already! I wish I can draw up a diagram - it would clearly illustrate the situation...

 

[daredevil123]

For a 1 degree difference on either side of the perpendicular, the difference (@200m straight line distance) is 3.5m
[tangent (1 degree) x 200m]

So NNB is seeing 7m wider at a distance of 200m, and 7m taller. Quite a lot

Even for 3 degrees, for subjects 200m away... still it is around 10m difference. But What I saw in NNB's shot is very very very much wider... Maybe my mind is playing tricks on me?

hmmmm. We will find out tomorrow.

 

[kriegsketten]

Even for 3 degrees, for subjects 200m away... still it is around 10m difference. But What I saw in NNB's shot is very very very much wider... Maybe my mind is playing tricks on me?

hmmmm. We will find out tomorrow.

Well, please do check on it and post images with detailed descriptions (object distance etc) for scientific research and break down analysis... :sweat:

 

[Shahmatt]

Full frame will give you a better dynamic range compared to a regular APS-C sensor.

Sheesh! Can't believe nobody has brought this up so far in this thread.