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Messages - dougkerr

Pages: 1 2 3 [4] 5 6
46
United Kingdom & Ireland / Re: Compatibility question
« on: August 16, 2011, 08:48:42 AM »
Hi, Casper,

Hi,
I own a Canon 450D at present but am waiting for the next release of the 5D.
In the meantime I'd like to buy a lens which would hopefully fit both. Is the Canon EF 85mm f/1.2L II USM compatible with both cameras?
Absolutely.

Note that when the lens is used on an EOS 5D, because of its larger sensor size than that of the 450D, the field of view will be greater.

Best regards,

Doug

47
Lenses / Re: Which is the best "normal" prime for a Crop Camera?
« on: August 13, 2011, 11:31:49 PM »
Hi, p,

I have a 7D and want to get a fast prime lens that would be close to the equivalent of a 50mm on a FF camera.
Well, the lens that, on an EOS 7D, would give the same field of view as would a 50 mm lens on a full-frame 35-mm camera would have a focal length of about 31 mm.

But you might mean something else by "would be close to equivalent".

Best regards,

Doug

48
Landscape / Re: Post Your Best Landscapes
« on: August 09, 2011, 03:03:04 PM »
Hi, K,

Just started doing HDR's .... Here is one I did recently
Very nice image.

What dynamic range does it have?

Thanks.

Best regards,

Doug

49
EOS Bodies / Re: 1Ds Mark IV Dimensions Outed?
« on: July 30, 2011, 05:15:04 PM »
That entry does not now seem to be in that table at Gigapan.

Best regards,

Doug

50
Canon General / Re: Canon 3 Layer Sensor (Foveon Type?) Patent
« on: July 07, 2011, 12:38:21 PM »
I wonder why they (Sgima) call it (SD1) 46Mp camera
Because it is a larger number.

Best regards,

Doug

51
EOS Bodies / Re: 36x36 mm cmos sensor
« on: June 10, 2011, 11:28:02 PM »
anybody sees any chance for a Canon EOS cmos-sensor that says goodbye to the 24x36mm "full-frame" limitation and actually provides the maximum format that the EOS optical system allows?

From my understanding, a 36x36 mm square format would be handled by any EF-lense without any issues. The EOS optical system is a circle, right - not an ellipse.
The largest square format that the current EF lens image circle (when an actual circle) could handle is 30.6 x 30.6 mm.

In some of the lenses, the image boundary is not quite a circle. Then a slightly smaller square format is all that could be handled.

Best regards,

Doug

52
Lenses / Re: Why did Canon make EF-S lenses
« on: June 08, 2011, 10:43:28 AM »
Hi, H,

Why did Canon make EF-S lenses

The object of the EF-S lens series is twofold:

• If the lens is not intended to be used on "full-frame 35-mm size" sensor cameras, but rather those with a smaller sensor size, it can have a smaller image circle, and this makes it easier to design for a certain set of optical properties with a certain optical performance.

• If the lens is not intended to be used "full-frame 35-mm size" sensor cameras, but rather those with a smaller sensor size (and thus a smaller reflex mirror, assuming an SLR arrangement), then the lens can have a smaller "back focus" (the physical distance from the rearmost point on the lens to the focal plane), which simplifies the design of lenses with smaller focal lengths.

Overall, then, we might expect that the objective is to allow the design of lenses for use only on "smaller-format" cameras that are less costly, smaller, and/or lighter, for given optical properties and optical performance, than if they were designed to be used on all cameras of the genre, including those with a full-frame 35-mm sensor size.

Note that the focal length quoted for EF-S lenses is (nominally) the "actual" focal length of the lens (the only focal length it has). It is an optical property of the lens, and does not presuppose its use in any particular format size camera . The lens has that property on any camera it will fit, or when in its carton.

The stating of the "full-frame 35-mm equivalent focal length" for a lens as it will be used on a camera of some particular format size, other than "full-frame 35-mm", is intended to allow the real property of interest, the field of view of the lens when used on that camera, to be expressed in a familiar, traditional form which can be compared to work with a full-frame 35-mm format camera. It is not an actual focal length of the lens under any circumstances.

Best regards,

Doug

53
EOS Bodies / Re: Very few EOS 1 bodies sold - wonder why!!
« on: June 01, 2011, 06:54:09 PM »
In the latest rumour it was mentioned that canon sell hardly any EOS 1 bodies relative to the 5D II.
Not too surprising - I don't think the EOS 1 has been made since about 1995.

Best regards,

Doug

54
Lenses / Re: Lens filter: step-down adapter ring, or not?
« on: April 22, 2011, 12:48:35 PM »
2. Get a step-down 77-72mm adapter ring
I think you are speaking of a 72-77 mm step-up adapter ring. (The description, both numerical and verbal, goes in the direction of lens size -> filter size.)

Here's an example:

http://www.bhphotovideo.com/c/product/98873-REG/General_Brand_72_77_72mm_77mm_Step_Up_Ring_Lens.html

Best regards,

Doug

55
EOS Bodies / Re: Question about RAW
« on: April 20, 2011, 10:50:06 PM »
My understanding of RAW is that it is simply the data "as-is" read from the sensor and saved on the memory card with no processing applied. However, I found that the color temp as set in a 50d directly affects the color temp of the saved RAW image. Are other in-camera functions applied to RAW as well?
The white balance color correction setting in the camera does not have any effect on the raw data.

However, that setting is saved (in a technically-detailed way) in the metadata of the raw file.

Then,  when the raw data is "developed" in external software to a JPEG or TIFF file, color correction is then applied, as set by the operator in any of various ways. One option is for the operator to tell the software to use the color correction that was set in the camera (which the software can read from the metadata) - the same color correction that the camera would have (or did) use in the in-camera generation of a JPEG file for the shot. But that is an explicit choice by the operator.

Best regards,

Doug

56
Canon General / Re: APS-C 11mm f/2 Patent
« on: April 06, 2011, 03:43:39 PM »
thank you for hitting my typo…..
Le crayon rouge ne dort jamais!

Best regards,

Doug

57
Canon General / Re: APS-C 11mm f/2 Patent
« on: April 06, 2011, 03:39:15 PM »
This patent is for a projection lens for an LCD-based video projector.

The corresponding US patent application is 2011/0038054.

Thanks to my colleague Hans Jørgensgaard for making the connection on this (he is my "go-to guy" on Canon patents)..

Best regards,

Doug

58
Canon General / Re: APS-C 11mm f/2 Patent
« on: April 05, 2011, 11:12:35 PM »
Lens

59
Software & Accessories / Re: Thoughts on 430EX
« on: March 25, 2011, 11:53:55 AM »
Thanks for dropping all this knowledge on us.  You are a true asset to the CR forum community.
Thank you so much. I find this forum very useful to my own interests.

Best regards,

Doug

60
Software & Accessories / Re: Thoughts on 430EX
« on: March 25, 2011, 11:23:02 AM »
Chuck Westfall of Canon USA has recently advised of a correction to his original summary of the circumstances in which the Speedlite 430EX (and 430EX II) flash units may operate in the multi-flash ("stroboscopic") mode.

He had originally said that the units could operate in that mode only when operating as a slave and the master is a Speedlite 550EX, 580EX, or 580EX II or the onboard flash unit of an EOS 7D.

He now advises that he has determined that in fact the multi-flash mode cannot be utilized by way of the onboard flash unit of an EOS 7D as a master. When that facility is set to the multi-flash mode, its operation as a master is disabled.

Thus, the Speedlite 430EX (or 430EX II) can only operate in the multi-flash mode when operating as a slave and the master is a Speedlite 550EX, 580EX, or 580EX II.

Again, to avert any misunderstanding, the 430EX (or 430EX II) apparently cannot provide the multi-flash mode when being directly operated from any camera, whether or not that camera provides for setting the associated flash.

Chuck's recent notice is here:

http://www.prophotohome.com/forum/canon-1-series-digital-slr-eos-5d/96337-speedlite-430ex-multi-flash-mode-chuck-2.html#post488749

Best regards,

Doug

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