Rokinon 14mm f/2.8 IF ED UMC Super Wide Angle Lens

4

480sparky

Senior Member
J-see said:
Yep since I had both types and shot both types on both formats and I'm certain that my 14mm FX doesn't have the same FoV on my DX than the 14mm length of my 10-24mm DX.

But if you don't agree, that's cool.

I'll just wait until I can say; told you so. ;)
Click to expand...


OK, once again:


We're not discussing the different sensor sizes here. The OP only has ONE sensor size... DX. The fact the both of us have FX camera is totally meaningless. So let's keep the discussion on that size sensor. Or would you like to add medium format, large format and CX format into the mix just to muddy the waters further?

And I will again reiterate: A 14mm lens ----whether it's designed for FX or DX----- WILL, I repeat WILL---- have a wider FOV on a DX sensor (what the OP has, and what we should be discussing... not OUR FX cameras!) than an 18mm. Doesn't matter whether that 18mm is an FX lens or DX lens. It doesn't matter whether the 14mm is FX or DX. A 14mm will have a wider FOV than the 18mm on a DX body.

It will. Simple as that.


What you don't seem to comprehend is that ANY focal length lens, whether FX or DX, -----will---- produce the same image on a DX sensor. It matter not whether the lens is 50mm FX or 50mm DX, or 14mm FX or 14mm DX, or 20.9485773mm DX or 20.9485773mm FX.

Now I gotta ask... what the heck is a 'true' 50mm?
 
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J

J-see

Senior Member
I'm still talking about the FoV. A 50mm DX lens is designed for a DX cam and will cast the full image on the sensor which results in the shot having the FoV of a 50mm. If you attach a 50mm FX lens, the FoV shrinks because the sensor is too small to "catch" the whole shot resulting in an equivalent FoV of 75mm or something on a 1.5x?


Which brings us back to his 14mm lens having the FoV of a 20-21mm equivalent on his DX and thus not being wider than his 18-55mm DX lens.
 
4

480sparky

Senior Member
J-see said:
I'm still talking about the FoV. A 50mm DX lens is designed for a DX cam and will cast the full image on the sensor which results in the shot having the FoV of a 50mm. If you attach a 50mm FX lens, the FoV shrinks because the sensor is too small to "catch" the whole shot resulting in an equivalent FoV of 75mm or something on a 1.5x?
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Incorrect. A 50mm DX lens will project an image large enough to cover the DX sensor. A 50mm FX lens will project an image large enough to cover an FX sensor, .................. but if both are placed on a DX camera............ they will be the same image.


J-see said:
Which brings us back to his 14mm lens having the FoV of a 20-21mm equivalent on his DX and thus not being wider than his 18-55mm DX lens.
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Once again, this is incorrect. It will NOT be the "FoV of a 20-21mm equivalent on his DX". It will be the FOV for a 14mm. The lens is 14mm. Period. It's immutable. Unchangeable. It's 14mm. And it will have the FOV a 14mm lens will have on a DX body.


Let's try this angle:

Specs from Nikons' web site:
14mm Nikkor FX lens: (AF Nikkor 14mm f/2.8D ED from Nikon)
FOV on DX: 90°

18-55 DX lens: (AF-S DX NIKKOR 18-55mm f/3.5-5.6G VR from Nikon)
FOV at 18mm on DX : 76°





From Samyangs website: (who makes the lens, and is rebranded as Rokinon)
14mm (Samyang Optics, Lenses for Camera – Cine – Photo - VDSLR, Prime Lenses & Third party Lenses)
FOV on DX: 93.9°


Both 14mm's are FX lenses.



J-see said:
Btw, if an FX and DX lens cast the exact same image on a DX cam, why did they bother developing DX lenses?
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DX lenses are smaller, lighter, and cheaper to make.... Designed for entry-level bodies and marketed as such. And they're usually slower than their FX counterparts.
 
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J

J-see

Senior Member
You're right. I got it wrong.

The equivalent FoV is in relation to the FoV of the lens on an FX. Whether the lens is DX or FX doesn't matter since on a DX cam they'll both have the same (DX) FoV. That it isn't the same as the FX is irrelevant in this case.

Thus the 14mm should be wider than the 18mm.


You got to get it wrong in order to get it right. ;)
 
hark

hark

Administrator
Staff member
Super Mod
If you are looking for a wider view than your 18mm, I'd suggest you check out a DX zoom that starts at either 11mm or 12mm. With the two lenses you already have, you won't see a huge amount of difference between your 14mm and your 18mm on DX. :)
 
4

480sparky

Senior Member
I think it's a curse on all modern photographers. The 'equivalent FOV' that's overly-touted by manufacturers just messes us up. And it's something that's very easy to get mixed up in.

Now, back to the OP.... how about some comparison shots between the two?
 
Bourbon Neat

Bourbon Neat

Senior Member
Copied from B&H photo, notice Angle of view:

Performance
Focal Length 14mm
Aperture Maximum: f/2.8
Minimum: f/22
Camera Mount Type Nikon F
Format Compatibility Nikon DX
Nikon FX/35mm Film
Angle of View 115.7°
APS-C Picture Angle: 93.9°
Minimum Focus Distance .9' (27.43 cm)
Elements/Groups 14/10
 
V

vmx12n

Senior Member
So to summarize for us noobs:

For a given camera sensor, an FX 50mm lens will look the same as a DX 50mm lens

but for a given lens, a camera body with an FX sensor will have a wider FoV than that same lens on a camera with a DX sensor.

Correct?
 
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J

J-see

Senior Member
vmx12n said:
So to summarize for us noobs:

For a given camera sensor, an FX 50mm lens will look the same as a DX 50mm lens

but for a given lens, a camera body with an FX sensor will have a wider FoV than that same lens on a camera with a DX sensor.

Correct?
Click to expand...

That's about it yeah.

The same wide on FX is wider than that wide on DX. ;)
 
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