enlargement from prime vs. telephoto

This is highly subjective but suppose I want to enlarge a portion of a
photo taken with a premium-quality 50mm lens to equal that of an image
area taken with a premium-quality 80mm lens. Approximately 50 percent
enlargement. Is the image with the 50 just 5/8s as clean as the same
image taken with the 80? What I'm getting at is this: how much do I
lose in final print quality by enlarging from a 50 as opposed to using
an 80? I'm sure brands make a difference and not all premium lenses at
given focal lengths are equal to other. But is there a rough rule of
thumb beyond the obvious fraction?

wrote:
This is highly subjective but suppose I want to enlarge a portion of a
photo taken with a premium-quality 50mm lens to equal that of an image
area taken with a premium-quality 80mm lens. Approximately 50 percent
enlargement. Is the image with the 50 just 5/8s as clean as the same
image taken with the 80? What I'm getting at is this: how much do I
lose in final print quality by enlarging from a 50 as opposed to using
an 80? I'm sure brands make a difference and not all premium lenses at
given focal lengths are equal to other. But is there a rough rule of
thumb beyond the obvious fraction?

Your calculation is close enough. The differences in film and lenses
also play in the real world results as does even the subject and lighting.


--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math

wrote:
This is highly subjective but suppose I want to enlarge a portion of a
photo taken with a premium-quality 50mm lens to equal that of an image
area taken with a premium-quality 80mm lens. Approximately 50 percent
enlargement. Is the image with the 50 just 5/8s as clean as the same
image taken with the 80? What I'm getting at is this: how much do I
lose in final print quality by enlarging from a 50 as opposed to using
an 80? I'm sure brands make a difference and not all premium lenses at
given focal lengths are equal to other. But is there a rough rule of
thumb beyond the obvious fraction?


You'll lose more than 50% quality:
At the film/sensor level, grain/pixels will be 50% bigger, resolution
50% less, partially SUMMED to a 50% reduction in lens resolution...

There are a lot of truly great short teles out there (even used): It
would be a pity to lose what they can offer!

Chris

wrote:
This is highly subjective but suppose I want to enlarge a portion of a
photo taken with a premium-quality 50mm lens to equal that of an image
area taken with a premium-quality 80mm lens. Approximately 50 percent
enlargement. Is the image with the 50 just 5/8s as clean as the same
image taken with the 80? What I'm getting at is this: how much do I
lose in final print quality by enlarging from a 50 as opposed to using
an 80? I'm sure brands make a difference and not all premium lenses at
given focal lengths are equal to other. But is there a rough rule of
thumb beyond the obvious fraction?


You'll lose more than 50% quality:
At the film/sensor level, grain/pixels will be 50% bigger, resolution
50% less, partially SUMMED to a 50% reduction in lens resolution...

There are a lot of truly great short teles out there (even used): It
would be a pity to lose what they can offer!

Chris

wrote:

This is highly subjective but suppose I want to enlarge a portion of a
photo taken with a premium-quality 50mm lens to equal that of an image
area taken with a premium-quality 80mm lens. Approximately 50 percent
enlargement. Is the image with the 50 just 5/8s as clean as the same
image taken with the 80? What I'm getting at is this: how much do I
lose in final print quality by enlarging from a 50 as opposed to using
an 80? I'm sure brands make a difference and not all premium lenses at
given focal lengths are equal to other. But is there a rough rule of
thumb beyond the obvious fraction?

If your image contained detail at the maximum resolution of lens and film (and
enlarger for that matter), then yes your fraction above is a reasonable quality
indicator. If the original contains less detail than that maximum, then there
should be less loss of sharpness perceived. Of course in nearly any image there
is some detail at the maximum res of the taking lens and film.

The middle section of the 80mm shot will be the sharpest. If your enlargement
takes from the edges/corners then those areas will be a bit softer.

Cheers,
Alan


--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

Chris Loffredo wrote:
wrote:
This is highly subjective but suppose I want to enlarge a portion of a
photo taken with a premium-quality 50mm lens to equal that of an image
area taken with a premium-quality 80mm lens. Approximately 50 percent
enlargement. Is the image with the 50 just 5/8s as clean as the same
image taken with the 80? What I'm getting at is this: how much do I
lose in final print quality by enlarging from a 50 as opposed to using
an 80? I'm sure brands make a difference and not all premium lenses at
given focal lengths are equal to other. But is there a rough rule of
thumb beyond the obvious fraction?


You'll lose more than 50% quality:
At the film/sensor level, grain/pixels will be 50% bigger, resolution
50% less, partially SUMMED to a 50% reduction in lens resolution...

There are a lot of truly great short teles out there (even used): It
would be a pity to lose what they can offer!

Chris

Maybe, but remember he will, I hope, be using the center area of the
image. The center area of the image is usually the sharpest, least distored
part of the image a lens can make. So in practice, that does reduce the
actural real life loss.

There are so many possible issues, I suggset the user, just give it a
try and see if he likes it. All the formulas and theories are nothing
compaired to the real thing. :-)

--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math

Alan Browne wrote:

wrote:

The middle section of the 80mm shot will be the sharpest. If your
enlargement takes from the edges/corners then those areas will be a bit
softer.

ooops ...meant 50mm obviously.

Cheers,
Alan


--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

Alan Browne wrote:

wrote:

The middle section of the 80mm shot will be the sharpest. If your
enlargement takes from the edges/corners then those areas will be a bit
softer.

ooops ...meant 50mm obviously.

Cheers,
Alan


--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

writes:

This is highly subjective but suppose I want to enlarge a portion of a
photo taken with a premium-quality 50mm lens to equal that of an image
area taken with a premium-quality 80mm lens.

I think there are other variables. While they all can be eliminated, on a
practical level I think nobody actually would. For a few examples, I think
most people would handhold the camera with both a 50 and an 80. (I had an
old Nikon rangefinder with an 8.5cm lens on it -- I never used a tripod.) I
also think most people would use full automatic exposure, and that the
camera would use different settings for the two lenses. If I were using the
two lenses on my FM2 and were unaware I were making a test shot, there's no
guarantee I'd use the same aperture and shutter speed. Given the different
lenses, I suspect I'd take too many things into account -- blurring the
background, using a faster shutter on the 80 to take into account the
longer lens -- to be able to judge whether the differences were the lens
or me.

I've read the answer to this, but I can't remember it: If I enlarge a
segment of an image taken with a 50mm lens to match the unenlarged image
from an 80mm, is the depth of field affected? I get confused about
perspective and whatever else changes. If DOF isn't changed, I think
determining whether the image quality is the same becomes more judgmental.

--
Philip Stripling | email to the replyto address is presumed
Legal Assistance on the Web | spam and read later. email to philip@
http://www.PhilipStripling.com/ | my domain is read daily.

writes:

This is highly subjective but suppose I want to enlarge a portion of a
photo taken with a premium-quality 50mm lens to equal that of an image
area taken with a premium-quality 80mm lens.

I think there are other variables. While they all can be eliminated, on a
practical level I think nobody actually would. For a few examples, I think
most people would handhold the camera with both a 50 and an 80. (I had an
old Nikon rangefinder with an 8.5cm lens on it -- I never used a tripod.) I
also think most people would use full automatic exposure, and that the
camera would use different settings for the two lenses. If I were using the
two lenses on my FM2 and were unaware I were making a test shot, there's no
guarantee I'd use the same aperture and shutter speed. Given the different
lenses, I suspect I'd take too many things into account -- blurring the
background, using a faster shutter on the 80 to take into account the
longer lens -- to be able to judge whether the differences were the lens
or me.

I've read the answer to this, but I can't remember it: If I enlarge a
segment of an image taken with a 50mm lens to match the unenlarged image
from an 80mm, is the depth of field affected? I get confused about
perspective and whatever else changes. If DOF isn't changed, I think
determining whether the image quality is the same becomes more judgmental.

--
Philip Stripling | email to the replyto address is presumed
Legal Assistance on the Web | spam and read later. email to philip@
http://www.PhilipStripling.com/ | my domain is read daily.