50mm 1.8G AF-S

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southwestsam

Senior Member
Just ordered myself the 50mm 1.8G prime after much reading of forums/reviews.

Really looking forward to taking some snaps with it. Would be good to see some of your pics taken with it too and any tips on techniques to use with it/best situations to use it in!
 
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gqtuazon

Gear Head
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southwestsam

Senior Member
Thanks Glenn, looks good! I have had a phonecall to say that it is arriving tomorrow :)

For anyone in the UK - Debenhams have it on sale at the moment (I know, strange place to shop for a lens!) £159 down to £143 which makes it cheaper than WEX etc.

As a side note, can someone clarify something for me...

I currently have the kit 18-55 which is specifically a DX lens. Will 50mm on the FX format 1.8G look the same as 50mm on my DX format 18-55, or will the crop factor make the 50mm appear as the equivalent of 75mm if I was using a DX format lens?
 
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Brian

Senior Member
Nikon does not use "relative focal length" but uses actual focal length on the DX format lenses. SO- 50mm on the "G" lens will look like the 50mm setting on the Zoom lens.

And- I did a few quick shots with the 50/1.8 "G" on the DF: it is very sharp. I bought the camera to use with manual focus lenses, but an aspheric F1.8 lens at that price, too good to pass up. It looks like a real winner.
 
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480sparky

Senior Member
Brian said:
Nikon does not use "relative focal length" but uses actual focal length on the DX format lenses..........
Click to expand...

Does this mean there's someone who DOES use 'relative focal length'? If so, who? I'm sure that causes more confusion than 'crop factor' does.
 
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southwestsam

Senior Member
I'm slightly confused now - if the 50mm FX will give the same FOV as a 50mm DX, then what is the difference between the 'standard' lenses and the DX specific ones? I can't get my head around how the FX will work with both sensor types but look the same as the DX?

Apologies for the lack of understanding - I just like to know how things work as well as being able to use them!

Also I have nothing else to distract me until tomorrow :p
 
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aroy

Senior Member
southwestsam said:
I'm slightly confused now - if the 50mm FX will give the same FOV as a 50mm DX, then what is the difference between the 'standard' lenses and the DX specific ones? I can't get my head around how the FX will work with both sensor types but look the same as the DX?

Apologies for the lack of understanding - I just like to know how things work as well as being able to use them!

Also I have nothing else to distract me until tomorrow :p
Click to expand...

The DX specific lenses have a small image circle that does not cover the full FX area. For reduced image circle a smaller diameter glass is used, hence the DX specific lenses are lighter and cheaper to manufacture compared to corresponding FX lenses. But when you use them with FX sensor you will not be able to cover beyond a diameter of approximately 24mm

The FX has larger image circle so the image subtended by FX lense will "overflow" the DX area - this is same as covering a small box (24mmx18mm in this case) with a large lid of 36mm diameter instead of a lid of 24mm diameter. There is nothing wrong with this except the lid is much larger than required.:cool:
 
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southwestsam

Senior Member
aroy said:
The FX has larger image circle so the image subtended by FX lense will "overflow" the DX area - this is same as covering a small box (24mmx18mm in this case) with a large lid of 36mm diameter instead of a lid of 24mm diameter. There is nothing wrong with this except the lid is much larger than required.:cool:
Click to expand...

So surely the result is the crop factor that would give the FX lens on a DX sensor a view of the scene equivalent (with the exception of the perception due to the narrower angle) to using a 75mm FX lens with an FX sensor?
 
Scott Murray

Scott Murray

Senior Member
Does this help?

Nikon-DX-vs-FX.jpg
 
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Steve B

Senior Member
People get hung up on this too often. Just remember that a smaller sensor will give you a smaller FOV for a specific focal length and that lenses specifically built for a smaller sensor format will not have an image circle large enough to cover a larger sensor. Good article here: Digital Camera Sensor Sizes: How it Influences Your Photography. Note the one section that states:
"The lens focal length does not change just because a lens is used on a different sized sensor — just its angle of view. A 50 mm lens is always a 50 mm lens, regardless of the sensor type. At the same time, "crop factor" may not be appropriate to describe very small sensors because the image is not necessarily cropped out (when using lenses designed for that sensor)."
 
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Lee532

Senior Member
Just ordered the 35mm 1.8G Af-S for use with my D5100, thought this would give me a field of view similar to a 50mm on my cropped sensor. Apparently. I'm not allowed it until Christmas though :(
 
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southwestsam

Senior Member
So the lens arrived today. It's amazing!!

It makes ordinary things look beautiful :D I think I might just have experienced what others refer to as NAS!
 
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