Canon lens test 300 f/4 L + 2x

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JohnR66 wrote:

> I reshot the test im more controlled conditions. I have more confidence in
> this combo now!
> http://home.att.net/~jriegle/canon300.htm
> John
>
>

The 300mm f/4 + 2x TC = f/8. If you are photographing with a
Canon 20D, 350 or other camera with with 6.4 micron pixels,
at f/5.6 the diffraction spot size is already larger than
the pixel spacing.

Diffraction spot size for green light:

f/4 = 5.2 microns
f/5.6 = 7.2
f/8 = 10
f/11 = 14
f/16 = 21

It is worse for red light, better for blue light.

All f/8 images would look softer than f/5.6 or f/4 if the lens
is performing near the diffraction limit.

Roger
http://www.clarkvision.com
 
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Most photos for long lens are 3D objects not 2D -- I understand why you are
testing a 2D print, but it would not be the normal domain of this lens and
TC combo -- more the domain of fix focal length MACRO, whcih canon has some
very good ones that have great sharpness and do great MACRO imaging with the
right technique and small set of tools

I would like to get a very good reach and touch combo for a 20D for birds
and an other wildlife --


"JohnR66" <nospam@att.net> wrote in message
news:dkXqe.940283$w62.20042@bgtnsc05-news.ops.worldnet.att.net...
>I reshot the test im more controlled conditions. I have more confidence in
>this combo now!
> http://home.att.net/~jriegle/canon300.htm
> John
>
 
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Archived from groups: rec.photo.digital (More info?)

"Steven Toney" <toneys@ibm.net> wrote in message
news:BtXqe.3020$hK3.2874@newsread3.news.pas.earthlink.net...
> Most photos for long lens are 3D objects not 2D -- I understand why you
> are testing a 2D print, but it would not be the normal domain of this lens
> and TC combo -- more the domain of fix focal length MACRO, whcih canon has
> some very good ones that have great sharpness and do great MACRO imaging
> with the right technique and small set of tools
>
> I would like to get a very good reach and touch combo for a 20D for birds
> and an other wildlife --
>
>
> "JohnR66" <nospam@att.net> wrote in message
> news:dkXqe.940283$w62.20042@bgtnsc05-news.ops.worldnet.att.net...
>>I reshot the test im more controlled conditions. I have more confidence in
>>this combo now!
>> http://home.att.net/~jriegle/canon300.htm
>> John
>>
>
>
I agree with what you said but the 2D test gets all parts of the image in
the focus plane for a quick go/nogo evaluation. Shooting through lots of
atmosphere is hard to get definitive results due to all the churning of the
air and thermal effects bending the light, causing blurring and distortions.
My first test was shooting through over 100 yards of air on a sunny day. A
bit unrealistic for shooting small birds where I'd be within 50 feet or so.
I need to put the combo through more field use to see how it performs. Out
of focus rendering (Bokeh) is nearly as important as the sharpness which the
2D test does not show.

I'll try to get shots of some birds to see if this set up is a workable
combo. I'd like to have the 500mm f/4 lens, but that's a dream...

John
 
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Archived from groups: rec.photo.digital (More info?)

My too purchase lens list is expensive, but I'd rather save a bit over time
and get the fastest glass with IS I can get even if delays getting the
lenses

I'm ramping up my digital photo time/learning and getting a long term set of
"toys" over the next few years as I approach retirement to have good set of
toys to play with when I have more time, but when the income lowers a bit --


"JohnR66" <nospam@att.net> wrote in message
news:UUXqe.940463$w62.214909@bgtnsc05-news.ops.worldnet.att.net...
> "Steven Toney" <toneys@ibm.net> wrote in message
> news:BtXqe.3020$hK3.2874@newsread3.news.pas.earthlink.net...
>> Most photos for long lens are 3D objects not 2D -- I understand why you
>> are testing a 2D print, but it would not be the normal domain of this
>> lens and TC combo -- more the domain of fix focal length MACRO, whcih
>> canon has some very good ones that have great sharpness and do great
>> MACRO imaging with the right technique and small set of tools
>>
>> I would like to get a very good reach and touch combo for a 20D for birds
>> and an other wildlife --
>>
>>
>> "JohnR66" <nospam@att.net> wrote in message
>> news:dkXqe.940283$w62.20042@bgtnsc05-news.ops.worldnet.att.net...
>>>I reshot the test im more controlled conditions. I have more confidence
>>>in this combo now!
>>> http://home.att.net/~jriegle/canon300.htm
>>> John
>>>
>>
>>
> I agree with what you said but the 2D test gets all parts of the image in
> the focus plane for a quick go/nogo evaluation. Shooting through lots of
> atmosphere is hard to get definitive results due to all the churning of
> the air and thermal effects bending the light, causing blurring and
> distortions. My first test was shooting through over 100 yards of air on a
> sunny day. A bit unrealistic for shooting small birds where I'd be within
> 50 feet or so.
> I need to put the combo through more field use to see how it performs. Out
> of focus rendering (Bokeh) is nearly as important as the sharpness which
> the 2D test does not show.
>
> I'll try to get shots of some birds to see if this set up is a workable
> combo. I'd like to have the 500mm f/4 lens, but that's a dream...
>
> John
>
>
 
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Archived from groups: rec.photo.digital (More info?)

In message <dkXqe.940283$w62.20042@bgtnsc05-news.ops.worldnet.att.net>,
"JohnR66" <nospam@att.net> wrote:

>I reshot the test im more controlled conditions. I have more confidence in
>this combo now!
>http://home.att.net/~jriegle/canon300.htm

Why were you surprised that the 300 f/4L was crisper than the 50mm
F/1.8?

There seems to be a myth going around that the 50mm Canon lenses are
their sharpest; this is not true at all. Many of the L telephotos are
much sharper than the 50mm lenses.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
 
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Here are a couple bird shots with the 300/4L and the 2x at ISO 400.

Mom feeds baby
http://home.att.net/~jriegle/grackle1.jpg

Grackle (full frame, just shrunk for the Web)
http://home.att.net/~jriegle/grackle2.jpg

At 20 feet, these birds are too big for the frame. At 30 feet, they fill the
frame. 60 or 70 feet would be the limits for song birds. Hope to get
something more interesting when I visit my parents place. They live in the
country, out in the woods where they see bluejays, blue birds, king fishers,
woodpeckers, hummingbirds and a dozen or so more.
John


>JohnR66" <nospam@att.net> wrote in message
>news:dkXqe.940283$w62.20042@bgtnsc05-news.ops.worldnet.att.net...
>I reshot the test im more controlled conditions. I have more confidence in
>this combo now!
> http://home.att.net/~jriegle/canon300.htm
> John
>
 
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