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Excellent $100 zoom, or Poor $250 prime?

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Jerry Hubbell

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Locust Grove, VA, US
I am a bit confused over the performance of the two lenses I have purchased thus far. I bought my SD9 kit with the very affordable 28-105mm F3.8-5.6 UC III zoom lens, and I purchased the glowingly reviewed 28mm F1.8 EX Asph prime lens. When I started using the 28mm prime, I suspected that I wasn't getting that much better perfomance (sharpness wise) than my zoom. I opted for the 28mm prime versus the 50mm prime, because I needed a wider angle for my aerial photo shots than the 50mm would provide.

Please see the link below for a comparison shot between the two.

Note: the lighting was slightly different between the two, although the exposure is the same. The cropped portion of the image I used is from a darker area of the photo. I used auto focus on both shots, with a solid lock on the focus.



This shows 2 double sized output files one from the prime, the other from the zoom. I was approximately 10ft from my bookcase. The exposure for both shots is F8.0 0.7sec. I had the zoom set to 28mm to match the prime.

Is it just me or do both images look pretty much the same as far as sharpness goes? Here is another view of the same images.



I took the double size images in photoshop and reduced each by 50% to see if the sharpening effect of reducing them would make a difference. Again they look pretty much the same to me.

Either one of two things are going on:

A. The cheap zoom I got is performing way above grade, and I am a lucky SOB.

B. The prime lens is not up to par and I should probably think about returning it for a new one.

I would like to think that it is A, but am prepared for B.

What do you think?

Thanks

jerry
 
Hi Jerry,

I don't yet own this cam, and am still considering lenses, so I find this very interesting.

I can tell a difference between the two.

In the first set, the first photo appears to be sharper to me (though not by much) than the second.

In the second set, the first photo not only appears sharper, but also seems to be showing a lot more detail in the shadow areas.

But from these crops, I can certainly see what you mean. There is not a huge difference.

So I'm wondering, were the crops taken more from the center of the photo or the edges?

Most of the Sigma lenses seem to have excellent sharpness in the center area of the lens, but the cheaper ones tend to start having problems along the edges and corners. It seems that with EX glass your largely looking for edge to edge sharpness, better lens speed and build quality, and less light fall off when stopping down.

I don't own any sigma lenses yet so I can't really say if what your seeing is "normal", so I am curious to hear from some users that do.

Regards,

Michael
Jerry Hubbell said:
I am a bit confused over the performance of the two lenses I have
purchased thus far. I bought my SD9 kit with the very affordable
28-105mm F3.8-5.6 UC III zoom lens, and I purchased the glowingly
reviewed 28mm F1.8 EX Asph prime lens. When I started using the
28mm prime, I suspected that I wasn't getting that much better
perfomance (sharpness wise) than my zoom. I opted for the 28mm
prime versus the 50mm prime, because I needed a wider angle for my
aerial photo shots than the 50mm would provide.

Please see the link below for a comparison shot between the two.
Note: the lighting was slightly different between the two, although
the exposure is the same. The cropped portion of the image I used
is from a darker area of the photo. I used auto focus on both
shots, with a solid lock on the focus.



This shows 2 double sized output files one from the prime, the
other from the zoom. I was approximately 10ft from my bookcase.
The exposure for both shots is F8.0 0.7sec. I had the zoom set to
28mm to match the prime.

Is it just me or do both images look pretty much the same as far as
sharpness goes? Here is another view of the same images.



I took the double size images in photoshop and reduced each by 50%
to see if the sharpening effect of reducing them would make a
difference. Again they look pretty much the same to me.

Either one of two things are going on:

A. The cheap zoom I got is performing way above grade, and I am a
lucky SOB.

B. The prime lens is not up to par and I should probably think
about returning it for a new one.

I would like to think that it is A, but am prepared for B.

What do you think?

Thanks

jerry
Click to expand...
 
Jerry Hubbell said:
Is it just me or do both images look pretty much the same as far as
sharpness goes?
Click to expand...
Can I assume these crops are from the centre?

Centre of field, f/8. Hmm. Wouldn't expect to see much difference, unless one of them was shot through a coke bottle.

Do the same comparison of a corner at f/4 and see if you can see the difference. I think you might just be able to ;-)

Finally, repeat at f/2... oh, the zoom can't do that, can it ;-)

Seriously, you need to do more comparisons, then decide for yourself which is the better lens. I don't think the results will surprise anybody.

--
Regards

John Bean
 
Thanks for the replies, Actually the crop is from the lower right side of the portrait mode image (which would be about 3/4's of the way to the lower left of a normal landscape mode image) Not really the corner but getting there. I will do the same test with the a crop from the center of the image to see if I can tell the difference there. I am interested in the sharpness at F8.0 since that is supposed to be in the sweet spot of the lenses. I will also take the photo with the flash to see if the amount of light (increased contrast) will make any subjective difference. I am beginning to think that I just maybe have been lucky with the zoom lens.

Jerry
John Bean (UK) said:
Jerry Hubbell said:
Is it just me or do both images look pretty much the same as far as
sharpness goes?
Click to expand...
Can I assume these crops are from the centre?

Centre of field, f/8. Hmm. Wouldn't expect to see much difference,
unless one of them was shot through a coke bottle.

Do the same comparison of a corner at f/4 and see if you can see
the difference. I think you might just be able to ;-)

Finally, repeat at f/2... oh, the zoom can't do that, can it ;-)

Seriously, you need to do more comparisons, then decide for
yourself which is the better lens. I don't think the results will
surprise anybody.

--
Regards

John Bean
Click to expand...
 
The second image is what I would expect from the two lenses at f8 in the center. The difference in the first set is less than I would expect. If you have time, take the 28 and do 3 AF images of the same subject (the one you used) at f8 and see if there is any difference. Use your timer and maybe even MLU since it is only 3 images. Your final view of the lens performance, given there is a difference but the question is degree, will be when you do a large print 11x16 or above.
--

.......Feel The Power.........Sigma.....SD9..........

http://www.lightreflection.com
http://www.silveroaksranch.com
http://www.pbase.com/rickdecker
http://www.pbase.com/sigmasd9/user_home
 
Thanks Rick for the input, I will do that... It sounds like your opinion is that both lenses are performing well and that this is normal. BTW I did use a tripod on both shots and the 2 second delay. The double size image does show a slight edge to the prime lens. As I have previously said, I thought that the zoom is quite a good value as lenses go. I will post some more comparisons soon.

Thanks
rick decker said:
The second image is what I would expect from the two lenses at f8
in the center. The difference in the first set is less than I
would expect. If you have time, take the 28 and do 3 AF images of
the same subject (the one you used) at f8 and see if there is any
difference. Use your timer and maybe even MLU since it is only 3
images. Your final view of the lens performance, given there is a
difference but the question is degree, will be when you do a large
print 11x16 or above.
--

.......Feel The Power.........Sigma.....SD9..........

http://www.lightreflection.com
http://www.silveroaksranch.com
http://www.pbase.com/rickdecker
http://www.pbase.com/sigmasd9/user_home
Click to expand...
 
In my lens tests I ran into some AF issues where I would shoot 5 shots and one or two would be noticeably softer at times than the other three. I tried to do everything the same to eliminate user error. One other person has mentioned having this happen. This is on a very limited basis and I don't remember what lens(es) did this. What are you shooting in batteries and if you are shooting rechargeable NIMH's, how are your numbers. If you are getting less than 150 shots, with the battery dying out (false battery readings and then the inability to restart the camera with the batteries after it shuts off), and want to do an experiment, could you call me at my toll-free, at 877-325-2300.

Thanks

Rick
Jerry Hubbell said:
Thanks
rick decker said:
The second image is what I would expect from the two lenses at f8
in the center. The difference in the first set is less than I
would expect. If you have time, take the 28 and do 3 AF images of
the same subject (the one you used) at f8 and see if there is any
difference. Use your timer and maybe even MLU since it is only 3
images. Your final view of the lens performance, given there is a
difference but the question is degree, will be when you do a large
print 11x16 or above.
--

.......Feel The Power.........Sigma.....SD9..........

http://www.lightreflection.com
http://www.silveroaksranch.com
http://www.pbase.com/rickdecker
http://www.pbase.com/sigmasd9/user_home
Click to expand...
Click to expand...
--

.......Feel The Power.........Sigma.....SD9..........

http://www.lightreflection.com
http://www.silveroaksranch.com
http://www.pbase.com/rickdecker
http://www.pbase.com/sigmasd9/user_home
 
Here is a link to a set of followup images.

http://www.pbase.com/image/20628205/original

(in case that doesn't work, here is another link to the large size
http://www.pbase.com/image/20628205/large )

I used a flash this time to add some light to see if this would subjectively change the results. The upper half were exposed F11.0 1/180 sec, and the lower half was F8.0 1/180 sec. The zoom lens is on the right hand side, and the prime on the left. These crops are at the center of the frame. You can see that by the ruler markings at the left and top of each image crop.

I used default processing in SPP (sharpening set to 0) and the exposures were pretty much dead on (exposure and contrast compensation + - 0.2) I saved the images as 8bit tiffs and brought them into photoshop so that I could create the quad image. No processing in photoshop. The images were saved as tiffs at standard size.

Does anyone else have images from the 28mm F1.8 EX that I can compare to these?

I am starting to think that the inexpensive zoom is a real bargain of a lens.

Thanks everyone for the input so far.

Jerry
Jerry Hubbell said:
I am a bit confused over the performance of the two lenses I have
purchased thus far. I bought my SD9 kit with the very affordable
28-105mm F3.8-5.6 UC III zoom lens, and I purchased the glowingly
reviewed 28mm F1.8 EX Asph prime lens. When I started using the
28mm prime, I suspected that I wasn't getting that much better
perfomance (sharpness wise) than my zoom. I opted for the 28mm
prime versus the 50mm prime, because I needed a wider angle for my
aerial photo shots than the 50mm would provide.

Please see the link below for a comparison shot between the two.
Note: the lighting was slightly different between the two, although
the exposure is the same. The cropped portion of the image I used
is from a darker area of the photo. I used auto focus on both
shots, with a solid lock on the focus.



This shows 2 double sized output files one from the prime, the
other from the zoom. I was approximately 10ft from my bookcase.
The exposure for both shots is F8.0 0.7sec. I had the zoom set to
28mm to match the prime.

Is it just me or do both images look pretty much the same as far as
sharpness goes? Here is another view of the same images.



I took the double size images in photoshop and reduced each by 50%
to see if the sharpening effect of reducing them would make a
difference. Again they look pretty much the same to me.

Either one of two things are going on:

A. The cheap zoom I got is performing way above grade, and I am a
lucky SOB.

B. The prime lens is not up to par and I should probably think
about returning it for a new one.

I would like to think that it is A, but am prepared for B.

What do you think?

Thanks

jerry
Click to expand...
 
When I got my SD9 I bought a cheap Sigma lens for walking around, 28-200 hyperzoom. I have found it to be very nice, and have not pulled my Nikor or Contax glass out since.
Jerry Hubbell said:
http://www.pbase.com/image/20628205/original

(in case that doesn't work, here is another link to the large size
http://www.pbase.com/image/20628205/large )

I used a flash this time to add some light to see if this would
subjectively change the results. The upper half were exposed F11.0
1/180 sec, and the lower half was F8.0 1/180 sec. The zoom lens is
on the right hand side, and the prime on the left. These crops are
at the center of the frame. You can see that by the ruler markings
at the left and top of each image crop.

I used default processing in SPP (sharpening set to 0) and the
exposures were pretty much dead on (exposure and contrast
compensation + - 0.2) I saved the images as 8bit tiffs and brought
them into photoshop so that I could create the quad image. No
processing in photoshop. The images were saved as tiffs at standard
size.

Does anyone else have images from the 28mm F1.8 EX that I can
compare to these?

I am starting to think that the inexpensive zoom is a real bargain
of a lens.

Thanks everyone for the input so far.

Jerry
Jerry Hubbell said:
I am a bit confused over the performance of the two lenses I have
purchased thus far. I bought my SD9 kit with the very affordable
28-105mm F3.8-5.6 UC III zoom lens, and I purchased the glowingly
reviewed 28mm F1.8 EX Asph prime lens. When I started using the
28mm prime, I suspected that I wasn't getting that much better
perfomance (sharpness wise) than my zoom. I opted for the 28mm
prime versus the 50mm prime, because I needed a wider angle for my
aerial photo shots than the 50mm would provide.

Please see the link below for a comparison shot between the two.
Note: the lighting was slightly different between the two, although
the exposure is the same. The cropped portion of the image I used
is from a darker area of the photo. I used auto focus on both
shots, with a solid lock on the focus.



This shows 2 double sized output files one from the prime, the
other from the zoom. I was approximately 10ft from my bookcase.
The exposure for both shots is F8.0 0.7sec. I had the zoom set to
28mm to match the prime.

Is it just me or do both images look pretty much the same as far as
sharpness goes? Here is another view of the same images.



I took the double size images in photoshop and reduced each by 50%
to see if the sharpening effect of reducing them would make a
difference. Again they look pretty much the same to me.

Either one of two things are going on:

A. The cheap zoom I got is performing way above grade, and I am a
lucky SOB.

B. The prime lens is not up to par and I should probably think
about returning it for a new one.

I would like to think that it is A, but am prepared for B.

What do you think?

Thanks

jerry
Click to expand...
Click to expand...
 
I would think you'd see much more of a difference in a test where the lenses were required to resolve small objects or fine detail at a greater distance. (Not to deny that the inexpensive zoom is a bargain.) Here's a shot taken with the 28mm, for your consideration.



full size here: http://www.pbase.com/image/20658404/original
Jerry Hubbell said:
Does anyone else have images from the 28mm F1.8 EX that I can
compare to these?

I am starting to think that the inexpensive zoom is a real bargain
of a lens.
Click to expand...
 
Well consider that you may got a good 100$ one and that the quality seems to greatly vary in that Lens segment.

And the major point is that your 100$ Lens won't produce those results at f1.8 ;)
Jerry Hubbell said:
I would have to agree, the prime is slightly better. I am still
impressed
with the $100 dollar lens.
Dominic Groß said:
--
Regards from Old Europe,

Dominic

http://www.pbase.com/sigmasd9/dominic_gross
Click to expand...
Click to expand...
--
Regards from Old Europe,

Dominic

http://www.pbase.com/sigmasd9/dominic_gross
 
You're right Dominic.... I would be very curious to see a comparison between the 50mm EX Macro and the $100 zoom that I have. Any one
have a spare they can send me for a test? :-)

Thanks again.
Dominic Groß said:
And the major point is that your 100$ Lens won't produce those
results at f1.8 ;)
Jerry Hubbell said:
I would have to agree, the prime is slightly better. I am still
impressed
with the $100 dollar lens.
Dominic Groß said:
--
Regards from Old Europe,

Dominic

http://www.pbase.com/sigmasd9/dominic_gross
Click to expand...
Click to expand...
--
Regards from Old Europe,

Dominic

http://www.pbase.com/sigmasd9/dominic_gross
Click to expand...
 
Horrible? Horrible? you haven't seen horrible until you see how
horrible this photo is

http://www.pbase.com/image/18704486/original

I would NEVER consider this a sharp photo..... NOT!!!!

I don't think you know what you are talking about Don and
in the future I will consider the source. Thank you for your
insightful critique
DonP said:
Jerry Hubbell said:
I would have to agree, the prime is slightly better. I am still
impressed
with the $100 dollar lens.
Dominic Groß said:
--
Regards from Old Europe,

Dominic

http://www.pbase.com/sigmasd9/dominic_gross
Click to expand...
Click to expand...
Click to expand...
 
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