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Messages - PavelR

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16
Lenses / Re: What exactly is a 100% crop?
« on: April 28, 2013, 07:29:18 AM »
drmikeinpdx

100% crop is like said here a few ways...
clip out a part of the full-sized shot...and dont resize it..

I use Faststone (a FREE photo utility you SHOULD have) for this stuff.. works great ...and on a series of photos keeps the same size you choose... for each consecutive pic...
in the 'Crop Board'  use 'lossless crop to file' 
you can set the size of the crop sample.....
the word sample is a hint....
... it automatically appends   _cr    to your native shot

so here is a recent Smith River Panorama ...with a 300x200 100% crop

hope that helps

TOM

I use Faststone to look over my RAW CF card sometimes... it CAN convert directly to jpg .. in a pinch...
it is VERY useful.....
+1

17
Lenses / Re: Which Lens Canon 85mm 1.8 or 135 L
« on: April 12, 2013, 05:39:01 PM »
Forgot to mention I shoot with a 6D.

I've shot with the Sigma and wasn't that impressed, but then again I was comparing it to the Canon. I don't want to pay that high of a price if similar image quality can be had with the Canon 1.8 at half the cost.

I have opposite personal experience with C85/1.8 and S85/1.4: Sigma = better IQ and AF.
(I switched from Nikon world to Canon and Nikkors 85/1.8 and 50/1.4 are far better, so I look for some adequate lenses and high price of Canon Ls and slow AF make me buy Sigma 85. I'm still looking for good 50 with AF...)

18
Reviews / Re: Review - Canon EF 8-15 f/4L Fisheye
« on: March 21, 2013, 08:02:10 PM »
Hi there, can I see samples with this lens with 1D IV
I can not imagine pictures on crop 1,3
or at leat explanation how it looks like.
thank you ...
OH
1.3x does not change the result significantly:

19
I don't have the 200/2 (so why am I replying?  :o ) but I don't understand this lens. The 70-200 is nearly as good, more versatile, smaller, lighter and cheaper. Other than for a few specialty uses why would you buy or use the 200? I think even the review here recently focused more on the use case of it being a good portrait lens. What else would you use the lens for?
The reason you do not understand this lens is: "you do not have one".
200/2 @ 2.8 is far better than 70-200II@200/2.8, thus I use it (200/2) anytime I do not need flexibility of the zoom (mostly outdoors) and/or need push ISO above 800 (or get rid of using a flash), than I switch to 200/2 and use it @ 2-2.8 to get better shutter speed.

20
Lenses / Re: Bridge not sharp - why?
« on: March 11, 2013, 05:36:10 AM »
I vote for motion blur (camera [wind...], engaged AF, ...). Try the similar shot (distance, F number) with more light / higher ISO and faster shutter speed - about 1/250 (1/320).

21
Lenses / Re: Addicted to dof
« on: March 06, 2013, 06:12:34 AM »
I've upgraded C 85/1.8 (purple fringing and inconsistent AF) to S 85/1.4 - all is better now - IQ, AF speed and consistency.
(My body is 1DIV.)

22
Lenses / Re: your goto everyday lens and why?
« on: March 04, 2013, 07:38:06 AM »
(I usually ride my bike slowly thru my hometown... along the river... only one lens [+body] sitting in my backpack.)

I was surprised by the lens choice as well, however this is hard to argue with, it sounds like a nice day  :)
... except for me, it would be a nice convertible, but that's details  ;)
The winter is finally passing...
(The pictures were taken in 2009 = long time before I bought Canon and 200/2.)

23
Lenses / Re: your goto everyday lens and why?
« on: March 04, 2013, 06:29:08 AM »
200mm f/2.0 you can't beat magic
+1
That's your everyday goto lens?
Yes, If I go "light" ;-) (only one lens) + not knowing exactly what I will be shooting...
200/2 produce the best subject isolation and is usable on 2, if the sun goes down...
For an evidence: I do not go to shoot every day - 99% of the time I'm shooting at weekend.
(I usually ride my bike slowly thru my hometown... along the river... only one lens [+body] sitting in my backpack.)

24
Lenses / Re: your goto everyday lens and why?
« on: March 04, 2013, 02:41:35 AM »
200mm f/2.0 you can't beat magic
+1

25
Technical Support / Re: Teleconverter and DOF
« on: March 01, 2013, 09:58:05 AM »
DOF will be smaller because of the bigger magnification.

If you crop the image taken w/o TC to the same framing of the other one, you get two identical results.

these kind of "explanation" are exactly why 80% don´t get it.   :P  :D
The first sentence is the definition of the change.
The second is the last step to produce the image that can be compared.
Anytime you cut some sentences from the article, you can get words that can not be understood...

26
Technical Support / Re: Teleconverter and DOF
« on: March 01, 2013, 09:50:21 AM »
DOF will be smaller because of the bigger magnification.
You can see it:
Take two photos - one with TC and one w/o TC.
If you crop the image taken w/o TC to the same framing of the other one, you get two identical results.
DOF is described perfectly at http://toothwalker.org/optics/dof.html

but that includes enlarging.
i guess you mean croping and enlarging to the same size as the other image?
i don´t want to imagine what that does with the COC.... and stuff.

and how can i get the same results when you first say the DOF is different?   ???
because when i enlarge the image the parts that appear sharp will then become unsharp?
because i enlarge the COC?

i want to know if i can calculate the DOF of a lens 100mm f2 + 1.4x TC the same way i would calculate a 140mm f2.8 lens.

if what neuroanatomist wrote is correct, and i can ignore the other stuff i have read (that lenses with the same physical aperture diameter have always the same DOF at the same focus distance).
Yes, I mean cropping and enlarging to the same physical size on the display / paper / ...
Difference can be seen on cropped and uncropped image (TC image is for getting adequate magnification).
I can not help you with math to calculate the DOF, because it depends on the final magnification ~ crop, lens sharpness, viewing distance, and many other factors, thus such number does mean nothing to me... (I need to know my lenses and predict the real result with different apertures; I do not want to convince anybody about the sharpness of the photo because DOF calculator says: it is in the DOF...)
There is another thread discussing DOF and background blur deeply: http://www.canonrumors.com/forum/index.php?topic=11109

27
Technical Support / Re: Teleconverter and DOF
« on: March 01, 2013, 08:44:47 AM »
DOF will be smaller because of the bigger magnification.
You can see it:
Take two photos - one with TC and one w/o TC.
If you crop the image taken w/o TC to the same framing of the other one, you get two identical results.
DOF is described perfectly at http://toothwalker.org/optics/dof.html


28
Lenses / Re: What are Canon's sharpest lenses?
« on: February 21, 2013, 05:29:42 PM »
Canon's sharpest lens:

300mm f/2.8 IS II

Canon's sharpest lens at f/2:

200mm f/2L IS

Canon's sharpest lens at f/1.4:

85L
+1

29
Speedlites, Printers, Accessories / Re: Where is this new flash?
« on: January 30, 2013, 05:52:57 AM »
Don't ever make a buying decision based on a rumor.  90+ percent do not happen.

I did it already 4 times ;-)
Long waiting, but I'm glad that I own new version now...

30
Lenses / Re: 200mm F2 IS OR 135mm F2
« on: January 24, 2013, 10:44:13 AM »
I own both and 85/1.4, the best IQ I get with F 2.8 and much better subject isolation is on 200mm.
(AF of 200/2 is also faster and the most consistent.)

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