Nikon Cheap Telephotos

[exemplaria]

I've got the 55-300mm VR. I'm thinking about getting the 70-300 VR. Would be a net cost to me of perhaps $150 after reselling. Worth it? The 70-300 seems to be the more popular lens around here, although the reviews of both lenses don't seem to scream one way or the other, especially at the 200-300 range.

My thought process is basically 1) Slightly better glass 2) Compatible with FX 3) I shoot DX so I'll get better performance from this FX lens using just the center. Thom Hogan says I should make the switch if price is no object, which at $150 it's not. Anyone want to disagree? Anyone? Bueller?

 

[Joves]

Well if you indeed want the lens I would not argue with you over that. The only drawback I can see is that of DX cropping of an FX lens, if you are using it as a walk around. But this will only affect you in wider field shots, since on the long end it is and advantage. And then the short end will only be a problem is you cannot frame a shot because you are unable to get enough distance from the subject. This and you do not state what other lenses you use as well. So the problem I pointed out is really the only one, and most of the times for me would not be much of one, I always carry extra glass for such occasions.

 

[exemplaria]

Would the field of vision be functionally the same, excepting of course the short end due to 55 vs 70?

 

[Joves]

Would the field of vision be functionally the same, excepting of course the short end due to 55 vs 70?

No not even close. It is easy to get the equivalent of any FX lens on a DX body just multiply the Focal Length by 1.5, in this case your 70s Field of View is 105mms, nearly half the FoV of the 55 since it is a DX, and the field is truly 55mm. As I said I do not know where you shoot of how much wide field you shoot, as opposed to distant shots. This only menas for wide you will have to move much further back to get the same composition.

 

[exemplaria]

Are you sure? I thought the crop factor applied regardless of whether it's a DX designated lens or not. The 55 on my current lens and 50 from my 50 f/1.8G (not a DX designated lens) are pretty similar.

 

[cgipson1]

I am sorry.. but a 55 is a 55, no matter what body you put it on..... the only thing different between the DX lenses and the FX lenses is that the DX are designed to utilize the whole lens instead of just he center. The Focal Length does not change....


Just like with a DX 35mm on a crop body... it is still a 35mm, even though FOV will be like a 50mm. It still has the standard 35mm attributes, like perspective distortion at close range.. that you would not have with a 50mm at the same distance

 

[Joves]

I am sorry.. but a 55 is a 55, no matter what body you put it on..... the only thing different between the DX lenses and the FX lenses is that the DX are designed to utilize the whole lens instead of just he center. The Focal Length does not change....


Just like with a DX 35mm on a crop body... it is still a 35mm, even though FOV will be like a 50mm. It still has the standard 35mm attributes, like perspective distortion at close range.. that you would not have with a 50mm at the same distance

You will note that at no time did I state the Focal Length changes only the Field of View, in that case the crop factor has a Focal Length FoV equivalent, which in the case of the 70mm has an FoV of a 105mm lens. The 55mm since it is a DX is 55mms since the lens is optimized for the crop sensor. The crop factor never changes that lenses properties only how it sees through that lens in the case of an FX lens. If that 55 was an FX then its FoV would not be the same as on DX camera. You people who read someone saying what the apparent field need to read more carefully. Want proof take a 105mm DX lens take a photo, then mount the 70mm FX lens on it, the scene will be exactly the same.

 

[480sparky]

You will note that at no time did I state the Focal Length changes only the Field of View, in that case the crop factor has a Focal Length FoV equivalent, which in the case of the 70mm has an FoV of a 105mm lens. The 55mm since it is a DX is 55mms since the lens is optimized for the crop sensor. The crop factor never changes that lenses properties only how it sees through that lens in the case of an FX lens. If that 55 was an FX then its FoV would not be the same as on DX camera. You people who read someone saying what the apparent field need to read more carefully. Want proof take a 105mm DX lens take a photo, then mount the 70mm FX lens on it, the scene will be exactly the same.

Try taking your own reading class.

Would the field of vision be functionally the same, excepting of course the short end due to 55 vs 70?

All he's asking is would there be any difference between the two lenses, other than losing the 55 to 70mm range. It isn't a 55mm v 70mm question. It isn't a crop v. FF question.

To exemplaria: The 70-300 will give you the exact same FOV the 55-300 will if you never took the 55-300 lower than 70mm.

 

[exemplaria]

Gents we can disagree and still be friends. Sparky has correctly characterized my question and given the answer I thought was correct. However I've been playing around with a few lenses and have results that just further confuse me more. I will post them in a bit.

 

[KmH]

the only thing different between the DX lenses and the FX lenses is that the DX are designed to utilize the whole lens instead of just he center. The Focal Length does not change....

That's really confusing.

True, the focal length does not change.

Both FX and DX lenses utilize the whole lens.
A DX lens projects a much smaller image circle than a FX lens does because a DX lens is designed to illuminate the smaller APS-C (crop) image sensor.
Consequently, a DX lens mounted on an Nikon FX camera body cannot fully illuminate the larger FX image sensor, though some DX lens can come close to fully illuminating the larger FX image sensor.

The smaller image circle a DX lens produces lowers the cost to make a DX lens compared to the cost to make the same lens a FX lens.

 

[emh]

FX lenses behave identically to DX lenses on a DX body in terms of focal length and field of view (provided both lenses are using the same settings, of course). The difference is that the FX lens has *the ability* to use the full area of an FF sensor to provide a wider FoV (without obscene vignetting) and the DX lens doesn't. But that ability is unused on a DX body.

 

[cgipson1]

the only thing different between the DX lenses and the FX lenses is that the DX are designed to utilize the whole lens instead of just he center. The Focal Length does not change....

That's really confusing.

True, the focal length does not change.

Both FX and DX lenses utilize the whole lens.
A DX lens projects a much smaller image circle than a FX lens does because a DX lens is designed to illuminate the smaller APS-C (crop) image sensor.
Consequently, a DX lens mounted on an Nikon FX camera body cannot fully illuminate the larger FX image sensor, though some DX lens can come close to fully illuminating the larger FX image sensor.

The smaller image circle a DX lens produces lowers the cost to make a DX lens compared to the cost to make the same lens a FX lens.

Smaller image circle.. yes.... where as the FX throws a larger image circle.. that doesn't all get used. Correct? Maybe the phrasing is backwards, but I was trying to say the same thing.

What about the "take a 105mm DX lens take a photo, then mount the 70mm FX lens on it, the scene will be exactly the same." A 105 is a 105 is a 105.. whether a DX or a FX... the only thing that changes is FOV, correct?

 

[480sparky]

The difference between a DX lens and an FX lens of the same focal length is the size of the AREA projected. The lenses projects a subject the same size.... it doesn't know which sensor is sitting behind it.

To show this, here's my D600 ("Full Frame/FX") and my D7000 ("Crop Sensor/DX"), side-by-side, with both in Mirror Up for Cleaning mode.



The blue-green rectangles are the actual sensors. Notice how the FX sensor on the left is larger (Nikon specs are 24m x 35.9mm) than the DX sensor on the right (Nikon: 23.6mm x 15.6mm)

I put a 50mm FX lens on the D600, it sees this:



When I put a 50mm DX on the D600, it sees this:



This is exactly what you would see in the viewfinder as well. (These images are merely reduced in scale for posting here. No other editing was done.) Notice how everything in the scene is rendered the same size?


The only difference between the two is the DX lens is not designed to cover the entire FX sensor.... it only needs to cover the smaller DX sensor. That's why the DX lens shows the black areas... both in the VF and on the sensor.

If I put either the FX OR the DX lens on the D7000 (crop sensor) , or on the D600 and shoot in DX mode, they will both record this:








When I enlarge the DX image to match the same dimension of the FX image, it appears I'm using a longer lens. I'm not. They're both 50mm. What changes is the field of view caused by the 'crop factor' of the smaller sensor.


An analogy would be like putting a film negative into an enlarger and running it up to make an 11x14. Then replace the 11x14 with a sheet of 8x10...... without changing anything else. The subjects in the 8x10 will measure the same as they are in the 11x14.

 

[cgipson1]

The difference between a DX lens and an FX lens of the same focal length is the size of the AREA projected. The lenses projects a subject the same size.... it doesn't know which sensor is sitting behind it.

To show this, here's my D600 ("Full Frame/FX") and my D7000 ("Crop Sensor/DX"), side-by-side, with both in Mirror Up for Cleaning mode.



The blue-green rectangles are the actual sensors. Notice how the FX sensor on the left is larger (Nikon specs are 24m x 35.9mm) than the DX sensor on the right (Nikon: 23.6mm x 15.6mm)

I put a 50mm FX lens on the D600, it sees this:



When I put a 50mm DX on the D600, it sees this:



This is exactly what you would see in the viewfinder as well. (These images are merely reduced in scale for posting here. No other editing was done.) Notice how everything in the scene is rendered the same size?


The only difference between the two is the DX lens is not designed to cover the entire FX sensor.... it only needs to cover the smaller DX sensor. That's why the DX lens shows the black areas... both in the VF and on the sensor.

If I put either the FX OR the DX lens on the D7000 (crop sensor) , or on the D600 and shoot in DX mode, they will both record this:








When I enlarge the DX image to match the same dimension of the FX image, it appears I'm using a longer lens. I'm not. They're both 50mm. What changes is the field of view caused by the 'crop factor' of the smaller sensor.


An analogy would be like putting a film negative into an enlarger and running it up to make an 11x14. Then replace the 11x14 with a sheet of 8x10...... without changing anything else. The subjects in the 8x10 will measure the same as they are in the 11x14.

Exactly!

 

[ratssass]

...it really did make it clearer for me when you (sparky) explained it in just this fashion.Should almost be a sticky,as I see it come up at least once a week.