Lens: Sigma 50mm f/2.8 DG macro
Vintage: current
Lens Mount: Nikon F-mount (comes in various camera-specific mounts)
Needed Adapters: None needed.
Preferred Mounting: Normal.
Filter Thread: 55 mm.
Controls: This lens has an aperture control and a focus limiting switch (close/full).
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Resolution vs Aperture:
The sharpest aperture is f/5.6, typical for a lens
of this focal length. The sharpness is nearly as
good from f/4.5 through f/6.3.
The most resolving aperture is f/4.5 although f/5
and f/5.6 are virtually the same (within 1%).
This means that f/5.6 is a good aperture to shoot
at for sharpness and resolution.
The sharpest aperture is f/5.6, typical for a lens
of this focal length. The sharpness is nearly as
good from f/4.5 through f/6.3.
The most resolving aperture is f/4.5 although f/5
and f/5.6 are virtually the same (within 1%).
This means that f/5.6 is a good aperture to shoot
at for sharpness and resolution.
Corner Sharpness vs Aperture:
The corner performance of this lens is extremely
good, even at large apertures, staying under
about 15%, and typically less than 10% across
the range.
(Testing done at 1:1 magnification. Numbers at
each aperture setting will tend to worsen slightly
as the magnification is decreased.)
The corner performance of this lens is extremely
good, even at large apertures, staying under
about 15%, and typically less than 10% across
the range.
(Testing done at 1:1 magnification. Numbers at
each aperture setting will tend to worsen slightly
as the magnification is decreased.)
Sharpness and Resolution vs Magnification:
This lens shows very high sharpness and
resolution across the macro range. The numbers
are only a touch below the Nikon 55 mm micro,
the best performer that I have come across to
date.
At 1:1 the MTF50 (sharpness) is about 1250
lw/ph, about as good as you are going to see.
The lens outresolves the D200 detector across
the board.
The price that you pay for this resolution is
relatively limited working distance - only 42 mm at
1:1. Compare that to a Nikon 105VR micro at
about 150 mm and the Nikon 200 micro at about
250 mm. More working distance means better
lighting (at least for coins).
The corner sharpness is very good across the
macro magnification range, less than 20% across
the range.
This lens shows very high sharpness and
resolution across the macro range. The numbers
are only a touch below the Nikon 55 mm micro,
the best performer that I have come across to
date.
At 1:1 the MTF50 (sharpness) is about 1250
lw/ph, about as good as you are going to see.
The lens outresolves the D200 detector across
the board.
The price that you pay for this resolution is
relatively limited working distance - only 42 mm at
1:1. Compare that to a Nikon 105VR micro at
about 150 mm and the Nikon 200 micro at about
250 mm. More working distance means better
lighting (at least for coins).
The corner sharpness is very good across the
macro magnification range, less than 20% across
the range.
Street Price: about $370 new.
Chromatic Aberration: This lens show minimal color fringing in the center
(less than 0.10 pixel) and good on the periphery (0.70 - 1.10 pixels). Anything
below 1.0 pixel is good.
(less than 0.10 pixel) and good on the periphery (0.70 - 1.10 pixels). Anything
below 1.0 pixel is good.
Image Contrast: Image contrast is good across the magnification range.
Flare: No significant flare is evident during lens testing
Conclusion:
This is an easy to find autofocus macro lens that is available in most lens mounts. It will only
autofocus on camera bodies that have an internal focus motor, but autofocus isn't all that useful
with macro anyway. The lens provides the viewfinder with a nice bright image (f/2.8), making
focusing easy.
This lens has very high sharpness and resolution across the macro magnification range and
performs at its best at f/5.6. The high resolution and sharpness is countered by the relative limited
working distance - you gotta pay somewhere. There is very little chromatic aberration and no visible
distortion. Corner sharpness is very good across the range, so this lens should be good for any
macro stitching you wish to do.
For me, I prefer to use shorter focal length macro lenses for imaging larger objects than coins. I
tend to run out of copystand height with longer focal lengths and larger objects.
So, I wouldn't tend to recommend this lens (or any of similar focal length) as a primary coin imaging
lens, although it will work OK if need be. This is mainly related to the limited working distance and
the lighting limitations that it imposes. For larger objects, it works very well. For imaging above 1:1
magnification, it should work well when reversed on a bellows, although I haven't tried it yet.
This is an easy to find autofocus macro lens that is available in most lens mounts. It will only
autofocus on camera bodies that have an internal focus motor, but autofocus isn't all that useful
with macro anyway. The lens provides the viewfinder with a nice bright image (f/2.8), making
focusing easy.
This lens has very high sharpness and resolution across the macro magnification range and
performs at its best at f/5.6. The high resolution and sharpness is countered by the relative limited
working distance - you gotta pay somewhere. There is very little chromatic aberration and no visible
distortion. Corner sharpness is very good across the range, so this lens should be good for any
macro stitching you wish to do.
For me, I prefer to use shorter focal length macro lenses for imaging larger objects than coins. I
tend to run out of copystand height with longer focal lengths and larger objects.
So, I wouldn't tend to recommend this lens (or any of similar focal length) as a primary coin imaging
lens, although it will work OK if need be. This is mainly related to the limited working distance and
the lighting limitations that it imposes. For larger objects, it works very well. For imaging above 1:1
magnification, it should work well when reversed on a bellows, although I haven't tried it yet.
Basic Function: Autofocus full function macro lens.
Appearance:
Aperture: 7 blades.
Image Samples:
About 1:2.5 magnification, f/5.6, cropped and resized:
About 1:2.5 magnification, f/5.6, 1 to 1 crop:
Good pixel level detail.
Good pixel level detail.
About 1:1, f/5.6, resized:
About 1:1 magnification, f/5.6, 1 to 1 crop:
Again, good detail, no problems.
Again, good detail, no problems.
Distortion: There is virtually no distortion with this lens. Straight lines on the
edge of the frame are straight on the image.
edge of the frame are straight on the image.
Performance: Sharpness vs Magnification:
This is a new graph that I recently constructed. I
have 4 lines that represent levels of performance
from outstanding (top) to fair (bottom). This
shows where this lens fit into the hierarchy that I
have created.
The Sigma 50mm shows outstanding sharpness
from 1:4 to 1:1, typical for a good short focal
length macro lens.
This is a new graph that I recently constructed. I
have 4 lines that represent levels of performance
from outstanding (top) to fair (bottom). This
shows where this lens fit into the hierarchy that I
have created.
The Sigma 50mm shows outstanding sharpness
from 1:4 to 1:1, typical for a good short focal
length macro lens.
Performance: Resolution vs Magnification:
This is a new graph that I recently constructed. I
have 4 lines that represent levels of performance
from outstanding (top) to fair (bottom). This
shows where this lens fit into the hierarchy that I
have created.
The Sigma 50mm shows outstanding resolution
performance throughout the range from 1:4 to
1:1, typical for a good short focal length macro
lens.
This is a new graph that I recently constructed. I
have 4 lines that represent levels of performance
from outstanding (top) to fair (bottom). This
shows where this lens fit into the hierarchy that I
have created.
The Sigma 50mm shows outstanding resolution
performance throughout the range from 1:4 to
1:1, typical for a good short focal length macro
lens.
