Difference in bokeh quality - same lens - Photography

[G.T.]

Removed by Administrator

[Chrlz]

Not a bokeh expert, but..

Yes, the nature of the background (contrasts/shapes) certainly can
affect the look of 'bokeh', even if it doesn't change the actual bokeh
itself. And of course the relative distance to the background will
also affect it, by changing how far out of focus it is.

And yes, a difference in zoom angle, or setting the lens into macro
mode (which for this lens probably involves moving internal elements)
could certainly affect it, and the aperture (and particularly the shape
of the aperture openeing at that setting) will affect it as well. I
don't see how shutter speed could make a difference, unless the
background was moving...!

In the examples you posted, it seems to me that the main difference is
that the background in the `nice` one (lovely shot by the way) is much
more out of focus - in fact if you look at the one stalk of wheat (?)
on the right that is much closer, it is beginning to show the same
`bad` bokeh... I might add, I've seen MUCH worse!

[paul]

OT: Yeah that's wheat and it is beautiful.

Chrlz wrote: 

[Paul]

G.T. <com> wrote:
 

The greater contrast in the first image highlights the donut shape of
the bokeh. You can especially see it in the white dots to the left.
There's also the compositional problem of the stem that pokes into focus
over the flower. It feels like it's poking you in the forehead. :-)

The second image doesn't have as much contrast in the background, so the
bokeh appears more even. If you look at the two highlighted leaves in
the bottom right, you can see the distinct edges of the blur, but that's
only because they're highlighted against a dark background. The rest of
that individual plant is suitably blurred, given the lack of contrast.
Nice pic. :-)

[G.T.]

"Paul Mitchum" <c0m> wrote in message
news:1gsicmv.mpk7hz1rjz219N%c0m... [/ref]
linear in [/ref]
shutter 
>
> The greater contrast in the first image highlights the donut shape of
> the bokeh. You can especially see it in the white dots to the left.[/ref]

Excellent, that explains it well.
 

Hahaha, yeah, I printed a version with that cropped out. When I added a
little more contrast that stem definitely looked like it was going to poke
an eye out.
 

Thanks.

Other than the Tamron having an extremely stiff zoom ring I'm pretty happy
with it.

This is another ladybug shot using it on my 300D:
http://homepage.mac.com/getosx/kimmie/ladybug1.jpg

Greg
--
"destroy your safe and happy lives before it is too late,
the battles we fought were long and hard,
just not to be consumed by rock n' roll" - the mekons

[Colin]

"G.T." wrote: 
Good macro shot, but I am more interested in your hand, specifically
that your third finger is considerably longer than the first. This
appears to be an unusual occurrence, as I also have the same longer
third finger, but I can find few other people with the same
characteristic.

Almost everyone's third finger is shorter than their first. (My first
finger is my trigger finger on my 300D, just to stay on topic {:-)

Colin.

[G.T.]

"Colin D" <127.0.0.1> wrote in message
news:127.0.0.1... 
> Good macro shot, but I am more interested in your hand, specifically
> that your third finger is considerably longer than the first. This
> appears to be an unusual occurrence, as I also have the same longer
> third finger, but I can find few other people with the same
> characteristic.
>[/ref]

Very interesting, I had never heard that before. My toes are interesting
lengths, too.

Greg

[Alan]

Colin D wrote:
 
>
> Good macro shot, but I am more interested in your hand, specifically
> that your third finger is considerably longer than the first. This
> appears to be an unusual occurrence, as I also have the same longer
> third finger, but I can find few other people with the same
> characteristic.[/ref]

My 3rd f. is longer than my 1st by about 5 and 10mm (left/right resp.).

The shot above is -not- macro.

Cheers,
Alan



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[G.T.]

"Alan Browne" <ca> wrote in message
news:cvnhlp$r4e$gazeta.pl... 
> >
> > Good macro shot, but I am more interested in your hand, specifically
> > that your third finger is considerably longer than the first. This
> > appears to be an unusual occurrence, as I also have the same longer
> > third finger, but I can find few other people with the same
> > characteristic.[/ref]
>
> My 3rd f. is longer than my 1st by about 5 and 10mm (left/right resp.).
>
> The shot above is -not- macro.[/ref]

You're right, it's not. But as pretty much a beginner what makes a macro
shot a macro shot?

The Tamron 24-135 says it's a macro lens, it focuses as close as 16" and the
mag ratio is 1:3.3. I didn't buy it as a macro lens so it doesn't matter to
me. I also have the Canon 100 2.8 macro which I didn't have along on the
above outing.

Greg

[Frank]

G.T. wrote:

<snip>
 

I guess you know that this excellent lens has compromised your personal
information: fingerprint!


--
Frank ess

[G.T.]

My fingerprint? I don't think so. That's a fake. Pretty good, huh?

[Chrlz]

I think true macro reproduction is meant to be 1:1 or greater! But
lens manufacturers seem to have hijacked the term and applied it to any
lens that can focus closer than about 12"... (O;

[Alan]

Chrlz wrote:
 

Yep. Real macros are 1:1 or better and not zoom.

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[G.T.]

"Alan Browne" <ca> wrote in message
news:cvql32$ggi$gazeta.pl... 
>
> Yep. Real macros are 1:1 or better and not zoom.
>[/ref]

As a beginner I'm not getting my head around the 1:1 ratio. What is being
compared there?

Thanks,
Greg
--
"destroy your safe and happy lives before it is too late,
the battles we fought were long and hard,
just not to be consumed by rock n' roll" - the mekons

[Alan]

G.T. wrote:
 
>>
>>Yep. Real macros are 1:1 or better and not zoom.
>>[/ref]
>
>
> As a beginner I'm not getting my head around the 1:1 ratio. What is being
> compared there?[/ref]

Very simply put, the image on the sensor is the exact same size as the subject.

For example, if you photograph an insect that is 10mm long at the closest focus
distance it will form an image 10mm long on the sensor (or film). This is a 1:1
magnification ratio.

For a Canon 20D, that would be about 1560 pixels, or a print of the 10mm insect
of over 5 inches (at 300 dpi).

SLR Macro lenses are typicaly fixed focal lenghts of 50, 100 (90, 100, 105) mm
and a few longer FL's (such as the Sigma 180 macro).

The only "true macro" zoom that I know of is the Minolta 50mm 3:1 f/1.7-2.8
power zoom macro lens. In this case you get true mag up to 3 times (which
doesn't sound like much until you see the photos n up on a slide
projector...). But this lens demands a lot of patience to learn to use effectively.

Not to be confused with zoom ratio (eg: where a camera manuf says this is a 3x
lens meaning the focal lenght ratio is 3:1 (eg: a 100-300mm lens has a 3:1 zoom
ratio, or "3x power" although)).

Hope that helps.

Cheers,
Alan.


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[G.T.]

"Alan Browne" <ca> wrote in message
news:cvqnn5$rfa$gazeta.pl... 
> >
> >
> > As a beginner I'm not getting my head around the 1:1 ratio. What is[/ref][/ref]
being 
>
> Very simply put, the image on the sensor is the exact same size as the[/ref]
subject. 
focus 
a 1:1 

Got it, thanks.
 
insect 
105) mm 

Yep, I have the Canon EF100.

One last question on this: how does the 1.6x conversion of my Rebel effect
the 1:1 ratio? I understand that it will be 1:1 on the sensor. I guess I
could do the numbers like you've done with 20D.

Thanks again,
Greg

[Slack]

On Fri, 25 Feb 2005 00:43:20 -0800, G.T. <com> wrote:
 
>> Good macro shot, but I am more interested in your hand, specifically
>> that your third finger is considerably longer than the first. This
>> appears to be an unusual occurrence, as I also have the same longer
>> third finger, but I can find few other people with the same
>> characteristic.
>>[/ref]
>
> Very interesting, I had never heard that before. My toes are interesting
> lengths, too.
>
> Greg
>
>[/ref]
That's because you're an alien freak!
--
Slack

[G.T.]

"Slack" <net> wrote in message
news:.. 
> >
> > Very interesting, I had never heard that before. My toes are[/ref][/ref]
interesting 
> That's because you're an alien freak![/ref]

Shhhhh. Please do not disseminate that information.

Greg

[Alan]

G.T. wrote:
 [/ref]
>
> being
> 
>>
>>Very simply put, the image on the sensor is the exact same size as the[/ref]
>
> subject.
> 
>
> focus
> 
>
> a 1:1
> 
>
>
> Got it, thanks.
>
> 
>
> insect
> 
>
> 105) mm
> 
>
>
> Yep, I have the Canon EF100.
>
> One last question on this: how does the 1.6x conversion of my Rebel effect
> the 1:1 ratio? I understand that it will be 1:1 on the sensor. I guess I
> could do the numbers like you've done with 20D.[/ref]

Again, it doesn't affect the image on the film plane at all. Just that the
overall image is cropped around the edges. For DRebel, just look up the sensor
width in pixels and mm and do the math.

Cheers,
alan


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-- e-meil: there's no such thing as a FreeLunch.