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Newbie question re. sharpness



 
 
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  #1  
Old December 10th 06, 06:42 PM posted to rec.photo.digital.slr-systems
gwperil
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Posts: 2
Default Newbie question re. sharpness

Hi,
I have what is hopefully a pretty basic question. I have a Canon 350D
with the two kit lenses:

* EF-S 18-55mm 1:3.5-5.6 II
* EF 75-300mm 1:4-5.6 III USM

As a test, I tried taking the "same" photo with each lens; that is, I
framed a still object as closely as possible with each lens and used
the same settings: Manual mode, 1/100s, f/5.6, ISO-100, Flash
(Speedlite 430EX pointed ahead), tripod. Obviously I had to move the
camera back to get the same shot with the 75-300. The only other
difference was of course the focal lengths: 45mm vs 75mm.

The picture taken with the 75-300 came out much sharper than with the
18-55. What accounts for that? I ask because, in general, I'm able to
get better looking pictures out of the 75-300.

Thanks in advance!

  #2  
Old December 10th 06, 08:10 PM posted to rec.photo.digital.slr-systems
John McWilliams
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Posts: 6,945
Default Newbie question re. sharpness

gwperil wrote:
Hi,
I have what is hopefully a pretty basic question. I have a Canon 350D
with the two kit lenses:

* EF-S 18-55mm 1:3.5-5.6 II
* EF 75-300mm 1:4-5.6 III USM

As a test, I tried taking the "same" photo with each lens; that is, I
framed a still object as closely as possible with each lens and used
the same settings: Manual mode, 1/100s, f/5.6, ISO-100, Flash
(Speedlite 430EX pointed ahead), tripod. Obviously I had to move the
camera back to get the same shot with the 75-300. The only other
difference was of course the focal lengths: 45mm vs 75mm.

The picture taken with the 75-300 came out much sharper than with the
18-55. What accounts for that? I ask because, in general, I'm able to
get better looking pictures out of the 75-300.


Better lens.

Can you easily post the two photos?

--
John McWilliams
  #3  
Old December 10th 06, 08:45 PM posted to rec.photo.digital.slr-systems
Charles Schuler
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Posts: 431
Default Newbie question re. sharpness



Can you easily post the two photos?

--
John McWilliams


I'd like to see them also.


  #4  
Old December 10th 06, 09:52 PM posted to rec.photo.digital.slr-systems
Aad
external usenet poster
 
Posts: 42
Default Newbie question re. sharpness


"gwperil" schreef in bericht
ups.com...
Hi,
I have what is hopefully a pretty basic question. I have a Canon 350D
with the two kit lenses:

* EF-S 18-55mm 1:3.5-5.6 II
* EF 75-300mm 1:4-5.6 III USM

As a test, I tried taking the "same" photo with each lens; that is, I
framed a still object as closely as possible with each lens and used
the same settings: Manual mode, 1/100s, f/5.6, ISO-100, Flash
(Speedlite 430EX pointed ahead), tripod. Obviously I had to move the
camera back to get the same shot with the 75-300. The only other
difference was of course the focal lengths: 45mm vs 75mm.

The picture taken with the 75-300 came out much sharper than with the
18-55. What accounts for that? I ask because, in general, I'm able to
get better looking pictures out of the 75-300.

Thanks in advance!

Both lenses are not producing very good pictures 'at the ends'.
So, don't use 18 and 55 or 75 and 300mm
Same for the aperture. Stay away from the ends.
Compare them again in the middle sections, ergo around 35mm and around
150mm, both with f8.
I think the difference will be less.
(beware that the largest apertures will become smaller when zoomin in. f5,6
will be wide-open in tele, dont't use it)
br
Aad


  #5  
Old December 10th 06, 10:17 PM posted to rec.photo.digital.slr-systems
Rudy Benner
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Posts: 124
Default Newbie question re. sharpness


"gwperil" wrote in message
ups.com...
Hi,
I have what is hopefully a pretty basic question. I have a Canon 350D
with the two kit lenses:

* EF-S 18-55mm 1:3.5-5.6 II
* EF 75-300mm 1:4-5.6 III USM

As a test, I tried taking the "same" photo with each lens; that is, I
framed a still object as closely as possible with each lens and used
the same settings: Manual mode, 1/100s, f/5.6, ISO-100, Flash
(Speedlite 430EX pointed ahead), tripod. Obviously I had to move the
camera back to get the same shot with the 75-300. The only other
difference was of course the focal lengths: 45mm vs 75mm.

The picture taken with the 75-300 came out much sharper than with the
18-55. What accounts for that? I ask because, in general, I'm able to
get better looking pictures out of the 75-300.

Thanks in advance!


Can you repeat the experiment without using the flash, use ambient light in
an open area?


  #6  
Old December 11th 06, 12:20 AM posted to rec.photo.digital.slr-systems
Floyd L. Davidson
external usenet poster
 
Posts: 5,138
Default Newbie question re. sharpness

"gwperil" wrote:
Hi,
I have what is hopefully a pretty basic question. I have a Canon 350D
with the two kit lenses:

* EF-S 18-55mm 1:3.5-5.6 II
* EF 75-300mm 1:4-5.6 III USM

As a test, I tried taking the "same" photo with each lens; that is, I
framed a still object as closely as possible with each lens and used
the same settings: Manual mode, 1/100s, f/5.6, ISO-100, Flash
(Speedlite 430EX pointed ahead), tripod. Obviously I had to move the
camera back to get the same shot with the 75-300. The only other
difference was of course the focal lengths: 45mm vs 75mm.

The picture taken with the 75-300 came out much sharper than with the
18-55. What accounts for that? I ask because, in general, I'm able to
get better looking pictures out of the 75-300.

Thanks in advance!


Trying to compare resolving power of two lenses is not as easy
as it first appears. One big problem with your configuration
was the use of flash, which will result in different lighting
for the two images, making them impossible to compare. I
suppose the ideal comparison is done between 11 AM and 1 PM on a
cloudy day, outside. :-)

Second, there are several comparisons that you'll want to know
about. At the middle of the zoom range, and at each end; plus
with the aperture wide open and with it stopped down to an
optimum opening and with it stopped down to f/16 or so. It
might also (depending on what you intend to shoot) be
interesting to do all of that with both close and distant
targets.

It generates a rather large amount of data. You may want to
limit it to that which appears to apply to your needs. For
example, if you do a lot of available light, then you do want to
compare at wider aperture, otherwise maybe not. If you do any
closeup work, then a close focus comparison is definitely
needed. If you shoot portraits, you'll want to compare in the
areas that match your portrait style.

Generally you do want to test the extremes of focal length and
aperture, because you want to know what the effects are when
there is no choice. Is it worth even trying to shoot with a
given lense wide open, or not? In what circumstances? For
example I have some lenses that I don't mind, or even prefer,
shooting wide open when making portraits, but would not think of
trying to focus up close on a flower or a bug and using that
same lense wide open.

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)
  #8  
Old December 11th 06, 08:39 AM posted to rec.photo.digital.slr-systems
Floyd L. Davidson
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Posts: 5,138
Default Newbie question re. sharpness

"default" wrote:

Looking through your website, I was wondering if you would share how you got
the Canon 800mm lens onto your Nikon? Since the Canon has a shorter
register distance, I presumed that you must have removed part of the rear of
the lens and put on a Nikon mount, but I was wondering if you could share
the details.


I don't really know the details, other than it is a rather well
done permanent conversion to a Nikon F mount on some kind of a
contract for a number of lenses (both Canon SSC 600mm f/4 and
800mm SSC f/5.6) by Tempe Camera Repair in Tempe AZ.

I'm not sure when was done, but assume that it would have been
modified in the late 70's or even early 80's. The lense was
designed for the 1976 Montreal Olympics, and was in production
until 1981, when Canon came out with a newer L version.

Adorama sold four or five each of the modified 600mm and 800mm
lenses on eBay. I've seen other odd lenses that Tempe Camera
had modified too, so apparently they did more than just a few.
All of them have been obviously well used, though also well
maintained, lenses. The one I have is in good condition, but
the case had clearly been shipped around the world a few times
and suffered the consequences. The outside was beat to pieces
while the inside was in very nice condition.

I considered it quite a find, because it sold for not only far
less than any other decent quality Nikon mount lense, the ones
modified for the Nikon mount sold for less than other unmodified
Canon 800mm lenses had sold for. It isn't like having an
autofocus lense, but that of course would cost thousands of
dollars more.

What is really astounding is that it works well with a selected
pair of telconverters, a 1.6x and a 2x, or with another specific
2x (I tested it with a number of different combination and
individual teleconverters to find ones that make a good match,
because most of them simply do not work well at all). Can you
imagine how hard it is to focus an 800mm lense with a 1.6x and a
2x teleconverter, making it into a 2560mm focal length! It
requires a *sturdy* tripod.

(Right now it is in the box, stored away, waiting for the sun to
come back up in late January. :-)

Presumably it would also be possible to put a Canon EF mount on in a
similiar manner and FD lenses are sooo cheap now ...

Of course there are adapters that allow infinity focus for Canon FD to EF,
but the real Canon one is expensive and rare, and the $40 is apparently not
great.


Tempe Camera Repair is still in business, and is a very
interesting outfit. I have no idea if they would consider doing
such modification today or not. Do a web search for them, it is
interesting reading!

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)
  #9  
Old December 11th 06, 01:55 PM posted to rec.photo.digital.slr-systems
gwperil
external usenet poster
 
Posts: 2
Default Newbie question re. sharpness

Rudy Benner wrote:
"gwperil" wrote in message
ups.com...
Hi,
I have what is hopefully a pretty basic question. I have a Canon 350D
with the two kit lenses:

* EF-S 18-55mm 1:3.5-5.6 II
* EF 75-300mm 1:4-5.6 III USM

As a test, I tried taking the "same" photo with each lens; that is, I
framed a still object as closely as possible with each lens and used
the same settings: Manual mode, 1/100s, f/5.6, ISO-100, Flash
(Speedlite 430EX pointed ahead), tripod. Obviously I had to move the
camera back to get the same shot with the 75-300. The only other
difference was of course the focal lengths: 45mm vs 75mm.

The picture taken with the 75-300 came out much sharper than with the
18-55. What accounts for that? I ask because, in general, I'm able to
get better looking pictures out of the 75-300.

Thanks in advance!


Can you repeat the experiment without using the flash, use ambient light in
an open area?


Thanks for everyone's comments on this.
I will take the advise of dropping the flash and going outside on a
cloudy day. Then I will find a place to post the photos.

Part of the reason for these tests is that I do not (yet) have the
experience to differentiate between bad technique and inferior
equipment... so as I consider a new lens, I want to measure the quality
of the two kit lenses as a reference point. There are a lot of strong
opinions out there with respect to lens quality. For example, I'm
interested in the EF 28-135mm F/3.5-5.6 IS USM lens. Research is all
over the map: "Perfect walk-around lens." "Way too soft." "IS is a
life-saver." "IS is not worth the money." And my personal favorite:
"Watch out for bad copies." Bad copies? There goes some more hair...

I guess there's no substitute for just plunking down the $$$ and trying
it out.

  #10  
Old December 11th 06, 10:36 PM posted to rec.photo.digital.slr-systems
Charles Schuler
external usenet poster
 
Posts: 431
Default Newbie question re. sharpness



Part of the reason for these tests is that I do not (yet) have the
experience to differentiate between bad technique and inferior
equipment... so as I consider a new lens, I want to measure the quality
of the two kit lenses as a reference point. There are a lot of strong
opinions out there with respect to lens quality. For example, I'm
interested in the EF 28-135mm F/3.5-5.6 IS USM lens. Research is all
over the map: "Perfect walk-around lens." "Way too soft." "IS is a
life-saver." "IS is not worth the money." And my personal favorite:
"Watch out for bad copies." Bad copies? There goes some more hair...

I guess there's no substitute for just plunking down the $$$ and trying
it out.


Or, you can use modulation transfer curves and make decisions based on how
you will most often use a particular lens:

http://www.usa.canon.com/consumer/co...mode lid=7445

By the way, the sharpness freaks can lead one astray. I have run tests
between two similar Canon zoom lenses, one of which was L-glass, and was
underwhelmed with the difference in sharpness. It was definitely there ...
I could see it; but honestly the difference was modest. Just me.

I'm not saying that L-glass is not worth it, by the way. Auto-focus
acquisition time and ruggedness are certainly worth having and paying for if
one has deep pockets or is a pro.


 




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