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Are DX lenses printed with the equivalent or actual focal lengths?

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nathanbush

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So I had a D90 before and used the kit lens, which I'm pretty sure was a DX lens. It was an 18-105mm. I found that I used it at 24mm almost all the time.

Now I shoot mostly with a D7000 and use both DX and FX lenses. My question is: do the DX lenses have the equivalent focal length printed on them, or the actual length? Someone told me the DX lenses do the math for you.

So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Hope that's clear.
 
nathanbush said:
So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Click to expand...
Incorrect. Let's take the Nikon 17-55 (DX lens) and the Nikon 24-70 (FX lens). Of course either will work on the D7000 but the Field of View of the 17-55 will be 25.5 - 82.5 while the 24-70 will have a Field of View of 36-105. Hence the 17-55 being the cropped sensor comparable lens to the 24-70. Some metadata readers will show you what the "35mm-equivalent" will be when shooting on a cropped sensor camera.
 
nathanleebush said:
So I had a D90 before and used the kit lens, which I'm pretty sure was a DX lens. It was an 18-105mm. I found that I used it at 24mm almost all the time.

Now I shoot mostly with a D7000 and use both DX and FX lenses. My question is: do the DX lenses have the equivalent focal length printed on them, or the actual length? Someone told me the DX lenses do the math for you.
Click to expand...
The lens always has the actual focal length marked on it.
nathanbush said:
So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Click to expand...
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
nathanbush said:
Hope that's clear.
Click to expand...
Me too.

Regards,
Peter
 
sherwoodpete said:
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Yes, 24mm may be the focal length. The focal length won't change using FX or DX. However, 24mm focal length on a cropped sensor camera will give you a Field of View of 36mm.
 
John Deerfield said:
John Deerfield said:
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Yes, 24mm may be the focal length. The focal length won't change using FX or DX. However, 24mm focal length on a cropped sensor camera will give you a Field of View of 36mm.
Click to expand...
A 24mm lens on a DX sensor camera will give you the Field of View of a 36mm lens on an FX camera.
 
Chas B said:
John Deerfield said:
Chas B said:
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Yes, 24mm may be the focal length. The focal length won't change using FX or DX. However, 24mm focal length on a cropped sensor camera will give you a Field of View of 36mm.
Click to expand...
A 24mm lens on a DX sensor camera will give you the Field of View of a 36mm lens on an FX camera.
Click to expand...
All of this crop has no purpose other than to confuse the O.P. It would have been better had he never seen it.

This is the answer:

All lenses that fit on Nikon DSLR's are marked with their actual focal lengths. A 24mm DX lens will have the same field as a 24mm FX lens.

--
Leonard Migliore
 
Leonard Migliore said:
All lenses that fit on Nikon DSLR's are marked with their actual focal lengths. A 24mm DX lens will have the same field as a 24mm FX lens.
Click to expand...
Yes. Let me emphasise that...

All lenses that fit on Nikon DSLRs are marked with their actual focal lengths. A 24mm DX lens will have the same field as a 24mm FX lens.
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"
 
Barrie Davis said:
Leonard Migliore said:
All lenses that fit on Nikon DSLR's are marked with their actual focal lengths. A 24mm DX lens will have the same field as a 24mm FX lens.
Click to expand...
Yes. Let me emphasise that...

All lenses that fit on Nikon DSLRs are marked with their actual focal lengths. A 24mm DX lens will have the same field as a 24mm FX lens.
Click to expand...
Yes, let me reemphasize (and correct) that.

All lenses that fit on Nikon DSLRs are marked with their actual focal lengths. On the same camera a 24mm DX lens will have the same field of view as a 24mm FX lens.
 
dradam said:
Barrie Davis said:
Leonard Migliore said:
All lenses that fit on Nikon DSLR's are marked with their actual focal lengths. A 24mm DX lens will have the same field as a 24mm FX lens.
Click to expand...
Yes. Let me emphasise that...

All lenses that fit on Nikon DSLRs are marked with their actual focal lengths. A 24mm DX lens will have the same field as a 24mm FX lens.
Click to expand...
Yes, let me reemphasize (and correct) that.

All lenses that fit on Nikon DSLRs are marked with their actual focal lengths. On the same camera a 24mm DX lens will have the same field of view as a 24mm FX lens.
Click to expand...
To be a little MORE accurate, perhaps it should be... any camera with the same size of sensor ....

... even non- Nikon ones, if you can get a special adaptor to make it fit. (NEX ??)
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"
 
Leonard Migliore said:
Chas B said:
John Deerfield said:
Leonard Migliore said:
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Yes, 24mm may be the focal length. The focal length won't change using FX or DX. However, 24mm focal length on a cropped sensor camera will give you a Field of View of 36mm.
Click to expand...
A 24mm lens on a DX sensor camera will give you the Field of View of a 36mm lens on an FX camera.
Click to expand...
All of this crop has no purpose other than to confuse the O.P. It would have been better had he never seen it.

This is the answer:

All lenses that fit on Nikon DSLR's are marked with their actual focal lengths. A 24mm DX lens will have the same field as a 24mm FX lens.
Click to expand...
Again, this is phrased in a confusing way. A more clear phrasing:
A 24mm DX lens will have the same field as a 24mm FX lens on a DX camera.
 
Nathan, let me apologize for the terrible responses you got to what is a very simple question: " Are DX lenses printed with the equivalent or actual focal lengths? "

The answer is one word: Actual ...

Knowing that, I sense that you can figure out all that other stuff... ;-)
nathanleebush said:
So I had a D90 before and used the kit lens, which I'm pretty sure was a DX lens. It was an 18-105mm. I found that I used it at 24mm almost all the time.

Now I shoot mostly with a D7000 and use both DX and FX lenses. My question is: do the DX lenses have the equivalent focal length printed on them, or the actual length? Someone told me the DX lenses do the math for you.

So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Hope that's clear.
Click to expand...
--
Charlie Davis
Nikon 5700, Sony R1, Nikon D50, Nikon D300
HomePage: http://www.1derful.info
"Quantum Mechanics: The dreams that stuff is made of..."
 
chuxter said:
Nathan, let me apologize for the terrible responses you got to what is a very simple question: " Are DX lenses printed with the equivalent or actual focal lengths? "
Click to expand...
You hardly need make an apology, since this is the first post you have made in this thread.

Regards,
Peter
 
sherwoodpete said:
nathanleebush said:
So I had a D90 before and used the kit lens, which I'm pretty sure was a DX lens. It was an 18-105mm. I found that I used it at 24mm almost all the time.

Now I shoot mostly with a D7000 and use both DX and FX lenses. My question is: do the DX lenses have the equivalent focal length printed on them, or the actual length? Someone told me the DX lenses do the math for you.
Click to expand...
The lens always has the actual focal length marked on it.
Click to expand...
Correct.
sherwoodpete said:
sherwoodpete said:
So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Click to expand...
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Incorrect. A 24mm lens on an APSC body will give a narrower field of view than the field of view on a full frame body.
sherwoodpete said:
sherwoodpete said:
Hope that's clear.
Click to expand...
Me too.

Regards,
Peter
Click to expand...
 
Chris59 said:
sherwoodpete said:
nathanleebush said:
So I had a D90 before and used the kit lens, which I'm pretty sure was a DX lens. It was an 18-105mm. I found that I used it at 24mm almost all the time.

Now I shoot mostly with a D7000 and use both DX and FX lenses. My question is: do the DX lenses have the equivalent focal length printed on them, or the actual length? Someone told me the DX lenses do the math for you.
Click to expand...
The lens always has the actual focal length marked on it.
Click to expand...
Correct.
Chris59 said:
Chris59 said:
So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Click to expand...
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Incorrect. A 24mm lens on an APSC body will give a narrower field of view than the field of view on a full frame body.
Click to expand...
NOT incorrect. [Read again, Chris.]
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"
 
Barrie Davis said:
Barrie Davis said:
Barrie Davis said:
Barrie Davis said:
So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Click to expand...
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Incorrect. A 24mm lens on an APSC body will give a narrower field of view than the field of view on a full frame body.
Click to expand...
NOT incorrect. [Read again, Chris.]
Click to expand...
Yes, he was right, but the way he wrote it, misinterpreting was easy to do. A better construction would have been:

" Yes. 24mm = 24mm. If used on a crop-sensor body, any 24mm focal length lens will have the same angle of view (unless it vignettes). "
Barrie Davis said:
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"
Click to expand...
--
Charlie Davis
Nikon 5700, Sony R1, Nikon D50, Nikon D300
HomePage: http://www.1derful.info
"Quantum Mechanics: The dreams that stuff is made of..."
 
Barrie Davis said:
Chris59 said:
sherwoodpete said:
nathanleebush said:
So I had a D90 before and used the kit lens, which I'm pretty sure was a DX lens. It was an 18-105mm. I found that I used it at 24mm almost all the time.

Now I shoot mostly with a D7000 and use both DX and FX lenses. My question is: do the DX lenses have the equivalent focal length printed on them, or the actual length? Someone told me the DX lenses do the math for you.
Click to expand...
The lens always has the actual focal length marked on it.
Click to expand...
Correct.
Barrie Davis said:
Barrie Davis said:
So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Click to expand...
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Incorrect. A 24mm lens on an APSC body will give a narrower field of view than the field of view on a full frame body.
Click to expand...
NOT incorrect. [Read again, Chris.]
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"
Click to expand...
Yes, incorrect. Although a 24mm lens remains a 24mm lens, (we will agree on that), the angle of view or field of view will be narrower for a DX lens than for an FX lens or for an FX lens on an APSC camera.

This is because the DX lens will have a smaller image circle while the FX lens on the APSC camera will have part of its image circle cropped.

Either way, even though the focal length of the lens remains the same, the field of view will be determined by the size of the image circle and/or the size of the sensor.
 
Chris59 said:
Barrie Davis said:
Chris59 said:
sherwoodpete said:
nathanleebush said:
So I had a D90 before and used the kit lens, which I'm pretty sure was a DX lens. It was an 18-105mm. I found that I used it at 24mm almost all the time.

Now I shoot mostly with a D7000 and use both DX and FX lenses. My question is: do the DX lenses have the equivalent focal length printed on them, or the actual length? Someone told me the DX lenses do the math for you.
Click to expand...
The lens always has the actual focal length marked on it.
Click to expand...
Correct.
Chris59 said:
Chris59 said:
So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Click to expand...
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Incorrect. A 24mm lens on an APSC body will give a narrower field of view than the field of view on a full frame body.
Click to expand...
NOT incorrect. [Read again, Chris.]
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"
Click to expand...
Yes, incorrect. Although a 24mm lens remains a 24mm lens, (we will agree on that), the angle of view or field of view will be narrower for a DX lens than for an FX lens or for an FX lens on an APSC camera.
Click to expand...
No! NOT incorrect, Chris!

If you HAD read it again, as suggested, you would have noticed you've been answering a question that has NOT been asked... whereas the question that WAS asked had already been correctly responded to.

Go directly to jail. Do not pass GO. Do not collect $200! :-)
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"
 
Barrie Davis said:
Chris59 said:
Barrie Davis said:
Chris59 said:
sherwoodpete said:
nathanleebush said:
So I had a D90 before and used the kit lens, which I'm pretty sure was a DX lens. It was an 18-105mm. I found that I used it at 24mm almost all the time.

Now I shoot mostly with a D7000 and use both DX and FX lenses. My question is: do the DX lenses have the equivalent focal length printed on them, or the actual length? Someone told me the DX lenses do the math for you.
Click to expand...
The lens always has the actual focal length marked on it.
Click to expand...
Correct.
Barrie Davis said:
Barrie Davis said:
So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Click to expand...
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Incorrect. A 24mm lens on an APSC body will give a narrower field of view than the field of view on a full frame body.
Click to expand...
NOT incorrect. [Read again, Chris.]
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"
Click to expand...
Yes, incorrect. Although a 24mm lens remains a 24mm lens, (we will agree on that), the angle of view or field of view will be narrower for a DX lens than for an FX lens or for an FX lens on an APSC camera.
Click to expand...
No! NOT incorrect, Chris!

If you HAD read it again, as suggested, you would have noticed you've been answering a question that has NOT been asked... whereas the question that WAS asked had already been correctly responded to.

Go directly to jail. Do not pass GO. Do not collect $200! :-)
--
Regards,
Baz
Click to expand...
I wasn't answering any questions, just correcting Sherwood Pete's incorrect statement about focal length and how it affects field of view.

It's time for you to read my posts again. I was not answering the OP's question, that had already been answered, but correcting the incorrect statement that because the marked focal length on a lens is indeed the actual focal length, it doesn't mean that the angle or field of view will be the same regardless of it being DX, FX or attached to an APSC sensor - it will not .
Barrie Davis said:
"Ahh... But the thing is, they were not just ORDINARY time travellers!"
Click to expand...
 
sherwoodpete said:
chuxter said:
Nathan, let me apologize for the terrible responses you got to what is a very simple question: " Are DX lenses printed with the equivalent or actual focal lengths? "
Click to expand...
You hardly need make an apology, since this is the first post you have made in this thread.
Click to expand...
It is not significant that my apology was my first post in this thread. I am often appalled that the "experts" here get off on a non-central issue with beginner's threads. Especially when they ask simple questions, it just seems wrong to have the experts argue about esoteric points, secondary to the central question. A little of this is good, because the OP gets a wider appreciation of photography...and some of the responses anticipate the OP's next question. I just thought in this case, it went too far off subject.

--
Charlie Davis
Nikon 5700, Sony R1, Nikon D50, Nikon D300
HomePage: http://www.1derful.info
"Quantum Mechanics: The dreams that stuff is made of..."
 
Chris59 said:
Chris59 said:
Chris59 said:
Chris59 said:
Chris59 said:
Chris59 said:
Chris59 said:
So in other words, if I put a regular Nikon full-frame lens on a crop-sensor body and use it at 24mm, is that the exact same field of view/image as a DX lens set to 24mm?
Click to expand...
Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.
Click to expand...
Incorrect. A 24mm lens on an APSC body will give a narrower field of view than the field of view on a full frame body.
Click to expand...
Click to expand...
Click to expand...
Click to expand...
Click to expand...
Chris59 said:
I wasn't answering any questions, just correcting Sherwood Pete's incorrect statement about focal length and how it affects field of view.

It's time for you to read my posts again. I was not answering the OP's question, that had already been answered, but correcting the incorrect statement that because the marked focal length on a lens is indeed the actual focal length, it doesn't mean that the angle or field of view will be the same regardless of it being DX, FX or attached to an APSC sensor - it will not .
Click to expand...
You're not reading.

its a not incorrect statement. Sherwood is saying that an FX and DX lens with the same focal length will produce the same angle of view on a DX sensor. Therefore a 24mm DX and FX lens will give you the same angle of view on a DX body.
 
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