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

Started Dec 10, 2010 | Discussions
nathanleebush
Junior MemberPosts: 28Gear list
Like?
Are DX lenses printed with the equivalent or actual focal lengths?
Dec 10, 2010

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.

 nathanleebush's gear list:nathanleebush's gear list
Sony RX100 II
John Deerfield
Senior MemberPosts: 2,080
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to nathanleebush, Dec 10, 2010

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?

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.

Reply   Reply with quote   Complain
sherwoodpete
Veteran MemberPosts: 7,761
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to nathanleebush, Dec 10, 2010

nathanleebush wrote:

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.

The lens always has the actual focal length marked on it.

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?

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

Hope that's clear.

Me too.

Regards,
Peter

Reply   Reply with quote   Complain
John Deerfield
Senior MemberPosts: 2,080
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to sherwoodpete, Dec 10, 2010

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

Reply   Reply with quote   Complain
Chas B
Senior MemberPosts: 1,021
Like?
Not quite clearly stated ...
In reply to John Deerfield, Dec 10, 2010

John Deerfield wrote:

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

A 24mm lens on a DX sensor camera will give you the Field of View of a 36mm lens on an FX camera.

Reply   Reply with quote   Complain
Leonard Migliore
Veteran MemberPosts: 9,768Gear list
Like?
That wasn't the question
In reply to Chas B, Dec 11, 2010

Chas B wrote:

John Deerfield wrote:

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

A 24mm lens on a DX sensor camera will give you the Field of View of a 36mm lens on an FX camera.

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.

-- hide signature --

Leonard Migliore

 Leonard Migliore's gear list:Leonard Migliore's gear list
Canon PowerShot G12 Nikon D300 Nikon AF-S DX Nikkor 16-85mm f/3.5-5.6G ED VR Nikon AF-S DX Nikkor 35mm f/1.8G Nikon AF-S DX Nikkor 10-24mm f/3-5-4.5G ED +9 more
Reply   Reply with quote   Complain
Barrie Davis
Forum ProPosts: 21,460
Like?
Agree
In reply to Leonard Migliore, Dec 11, 2010

Leonard Migliore wrote:

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.

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!"

Reply   Reply with quote   Complain
dradam
Senior MemberPosts: 2,593
Like?
Re: Agree
In reply to Barrie Davis, Dec 11, 2010

Barrie Davis wrote:

Leonard Migliore wrote:

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.

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.

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.

Reply   Reply with quote   Complain
Barrie Davis
Forum ProPosts: 21,460
Like?
Re: Agree
In reply to dradam, Dec 11, 2010

dradam wrote:

Barrie Davis wrote:

Leonard Migliore wrote:

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.

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.

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.

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!"

Reply   Reply with quote   Complain
Chas B
Senior MemberPosts: 1,021
Like?
And that wasn't the answer
In reply to Leonard Migliore, Dec 11, 2010

Leonard Migliore wrote:

Chas B wrote:

John Deerfield wrote:

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

A 24mm lens on a DX sensor camera will give you the Field of View of a 36mm lens on an FX camera.

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.

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.

Reply   Reply with quote   Complain
chuxter
Forum ProPosts: 13,542Gear list
Like?
The best answer!
In reply to nathanleebush, Dec 11, 2010

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 wrote:

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.

-- hide signature --

Charlie Davis
Nikon 5700, Sony R1, Nikon D50, Nikon D300
HomePage: http://www.1derful.info
"Quantum Mechanics: The dreams that stuff is made of..."

Reply   Reply with quote   Complain
sherwoodpete
Veteran MemberPosts: 7,761
Like?
No need for an apology
In reply to chuxter, Dec 11, 2010

chuxter wrote:

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? "

You hardly need make an apology, since this is the first post you have made in this thread.

Regards,
Peter

Reply   Reply with quote   Complain
Chris59
Veteran MemberPosts: 6,143Gear list
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to sherwoodpete, Dec 12, 2010

sherwoodpete wrote:

nathanleebush wrote:

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.

The lens always has the actual focal length marked on it.

Correct.

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?

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

Hope that's clear.

Me too.

Regards,
Peter

Reply   Reply with quote   Complain
Barrie Davis
Forum ProPosts: 21,460
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to Chris59, Dec 12, 2010

Chris59 wrote:

sherwoodpete wrote:

nathanleebush wrote:

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.

The lens always has the actual focal length marked on it.

Correct.

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?

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

NOT incorrect. [Read again, Chris.]
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"

Reply   Reply with quote   Complain
chuxter
Forum ProPosts: 13,542Gear list
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to Barrie Davis, Dec 12, 2010

Barrie Davis wrote:

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?

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

NOT incorrect. [Read again, Chris.]

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). "

-- hide signature --

Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"

-- hide signature --

Charlie Davis
Nikon 5700, Sony R1, Nikon D50, Nikon D300
HomePage: http://www.1derful.info
"Quantum Mechanics: The dreams that stuff is made of..."

Reply   Reply with quote   Complain
Chris59
Veteran MemberPosts: 6,143Gear list
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to Barrie Davis, Dec 13, 2010

Barrie Davis wrote:

Chris59 wrote:

sherwoodpete wrote:

nathanleebush wrote:

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.

The lens always has the actual focal length marked on it.

Correct.

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?

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

NOT incorrect. [Read again, Chris.]
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"

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.

Reply   Reply with quote   Complain
Barrie Davis
Forum ProPosts: 21,460
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to Chris59, Dec 13, 2010

Chris59 wrote:

Barrie Davis wrote:

Chris59 wrote:

sherwoodpete wrote:

nathanleebush wrote:

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.

The lens always has the actual focal length marked on it.

Correct.

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?

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

NOT incorrect. [Read again, Chris.]
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"

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.

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!"

Reply   Reply with quote   Complain
Chris59
Veteran MemberPosts: 6,143Gear list
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to Barrie Davis, Dec 13, 2010

Barrie Davis wrote:

Chris59 wrote:

Barrie Davis wrote:

Chris59 wrote:

sherwoodpete wrote:

nathanleebush wrote:

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.

The lens always has the actual focal length marked on it.

Correct.

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?

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

NOT incorrect. [Read again, Chris.]
--
Regards,
Baz

"Ahh... But the thing is, they were not just ORDINARY time travellers!"

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.

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

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 .

"Ahh... But the thing is, they were not just ORDINARY time travellers!"

Reply   Reply with quote   Complain
chuxter
Forum ProPosts: 13,542Gear list
Like?
Re: No need for an apology
In reply to sherwoodpete, Dec 13, 2010

sherwoodpete wrote:

chuxter wrote:

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? "

You hardly need make an apology, since this is the first post you have made in this thread.

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.

-- hide signature --

Charlie Davis
Nikon 5700, Sony R1, Nikon D50, Nikon D300
HomePage: http://www.1derful.info
"Quantum Mechanics: The dreams that stuff is made of..."

Reply   Reply with quote   Complain
sengngo
Junior MemberPosts: 44
Like?
Re: Are DX lenses printed with the equivalent or actual focal lengths?
In reply to Chris59, Dec 13, 2010

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?

Yes. 24mm = 24mm. If used on a crop-sensor body the angle of view will be the same for both cases.

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.

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 .

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.

Reply   Reply with quote   Complain
Keyboard shortcuts:
FForum MMy threads