Should a nifty 50......

Grockle

Grockle

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Chris
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....be a fun 31 or a great 38 for those of us using 1.6 or 1.3 crop sensors?

If so, why? If not, why not?
 
Surely its an 80 or a 65 respectively.
 
hyakuhei said:
Surely its an 80 or a 65 respectively.
Click to expand...

:agree:

These are the 'effective' focal lengths (more FoV equivalents actually) of a 50mm on those crop sensors

If you were saying...

"I want a 50mm focal length FoV, is a 31mm or 38mm lens suitable to give the equivalent of a 50mm on a FF sensor, with a 1.6 and 1.3 crop respectively?"

Then yes :thumbs:

Just remember that with 'crop' sensors (and that's relative to a FF one) the crop effectively magnifies the focal length in a similar way to putting a 1.6 or 1.3 convertor would do on the FF body

HTH :shrug:

DD
 
DD - at least you can follow my possibly strange way of thinking.

The way so many people rant about how good the 50 is as a prime lens then to my way of thinking, if you want to be able to get the equivalent field of view on a crop sensor camera, then you have to divide rather than multiply.
 
You're contradicting yourself up there DD

Putting a 1.6 converter on a FF body would increase magnification, using a smaller (1.6 crop) sensor would only decrease the field of view.
 
Grockle said:
DD - at least you can follow my possibly strange way of thinking.

The way so many people rant about how good the 50 is as a prime lens then to my way of thinking, if you want to be able to get the equivalent field of view on a crop sensor camera, then you have to divide rather than multiply.
Click to expand...

Yep :thumbs:

But when peeps refer to the wonderful 'Nifty fifty' I think they usually mean as it's a useful focal length and with the very wide aperture for little money, it looks to be a good buy overall

Not sure they are always meaning the FoV of a 50mm as such as we older ones know it from the 35mm film days

An awful lot of digi peeps I suspect have never used a 35mm film camera and can't easily appreciate the effect of the crop, so to them the 'crop factor' is actually meaningless

DD
 
Steep said:
You're contradicting yourself up there DD

Putting a 1.6 converter on a FF body would increase magnification, using a smaller (1.6 crop) sensor would only decrease the field of view.
Click to expand...

If you increase the magnification don't you restrict (i.e. crop) your FoV too relative to the lens without the convertor on it???

:thinking:

DD
 
Yes DD, but decreasing the fov (i.e. 1.6 crop) doesn't increase the magnification.
 
Steep said:
Yes DD, but decreasing the fov (i.e. 1.6 crop) doesn't increase the magnification.
Click to expand...

Surely it has the effect of increasing the apparent power of the lens, which is like magnifying a part of the image :shrug:

Or are we just splitting hairs for the sake of it???

If my 12 mp covers 50 degrees on a FF sensor and I have the same 12 mp on 31 degrees of the same view on a crop sensor, how can that not be explained using the word 'magnify' ???

Seems a reasonable explanation to me :thinking:

:)

DD
 
Dave Scanlon said:
:agree: a 50 on a 1.6 crop becomes an excellent 80 mm portrait lens :rules:
Click to expand...

that isn't correct. 50mm on a crop sensor still gives the perspective of 50mm on a full frame. this is not a particularly flattering focal length 80mm upwards is a far more flattering focal length as far as perspective are concerned. it has nothing to do with how far away from the subject you have to shoot.
 
? your article shows me to be correct. taking portrait photos with longer lenses is to avoid the unflattering perspective give on wider lenses. using a cropped sensor doesn't change this, it merely crops the edge off your image.
 
wow, another useless KR article. he makes no mention of the fact that on a crop vs FF sensor there is no difference in DOF or perspective, it is only a crop. oh and i should clarify:

when i say this:
it has nothing to do with how far away from the subject you have to shoot.
Click to expand...
I am describing what makes (or doesn't make in this case) the lens a 'portrait lens'.
 
ruvor said:
? your article shows me to be correct. taking portrait photos with longer lenses is to avoid the unflattering perspective give on wider lenses. using a cropped sensor doesn't change this, it merely crops the edge off your image.
Click to expand...


What do you think a longer lens does? Perspective is purely a product of position and distance from subject. Since a wide angle lens has a larger field of view you have to be closer to the subject to file the frame. Since your closer then the apparent perspective differences between different parts of the subject become accentuated. Noses look bigger etc.

The longer the focal length of the lens the larger the "image" that is projected on the focal plane. If you assume an infinite lens and sensor/film resolution then there is absolutely no difference between cropping the image and using a larger focal length lens. The only reason we need longer focal lengths is that lens and film resolution is NOT infinite so there is a limit to how much we can crop.
 
DiddyDave said:
Surely it has the effect of increasing the apparent power of the lens, which is like magnifying a part of the image :shrug:

Or are we just splitting hairs for the sake of it???

If my 12 mp covers 50 degrees on a FF sensor and I have the same 12 mp on 31 degrees of the same view on a crop sensor, how can that not be explained using the word 'magnify' ???

Seems a reasonable explanation to me :thinking:

:)

DD
Click to expand...

Not splitting hairs, just trying to get the facts right.

Try using the word enlarge/d applied to the image after it's been taken, not magnified by the lens before it's been taken.

Having 12mp on a smaller sensor 'should' allow you to enlarge the taken image more without losing quality but it's a function of the computer not the lens. A 50mm lens magnifies the subject by the same amount regardless of what it's attached to, so the extra pixels do not give you longer reach.

Example, I take a shot of a person with a 50mm lens, then take another with a 500mm lens. The 50mm shot shows a tiny red dot on their nose, the 500mm lens shows the red dot is a ladybird. No matter how many pixels on the sensor they can't resolve detail that the lens doesn't supply.
 
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