Messages

61

EOS Bodies / Re: Canon Doesn't Need a Compact Camera System

« on: March 21, 2011, 09:00:03 PM »

Some sort of kerr cell shutter. The mirror only becomes semi-transparent with an electrical impulse.

Oh, interesting thought.

Not invented by me, by the way - by a cousin, we assume.

Best regards,

Doug

62

EOS Bodies / Re: Canon Doesn't Need a Compact Camera System

« on: March 21, 2011, 08:26:40 PM »

Id love to see a mirrorless canon FD mount system, . . .

[/quote]
You mean no autofocus, mechanical aperture control?

. . . adapter for new lenses.

What kind of new lenses? They would have to have a back flange distance of at least 50mm or so (could not even be EF lenses).

Best regards,

Doug

63

EOS Bodies / Re: Canon Doesn't Need a Compact Camera System

« on: March 21, 2011, 08:05:09 PM »

Is it possible to make a pellix mirror that "somehow" doesn't dim the viewfinder while framing?

Pellix is the tradename of a Canon camera. It uses a fixed, semi-reflective pellicle mirror (a mirror whose substrate is a stretched thin film - the term itself does not imply anything else about the mirror) in a single-lens reflex configuration.

A single-lens reflex camera using a fixed semi-reflective mirror can have a mirror box that is a bit shorter than the mirror box for a moving mirror system.

A fixed semi-reflective mirror in a single-lens reflex camera (pellicle or otherwise) inevitably results in some light loss in both the taking and viewing paths.

What kind of arrangement do you have in mind?

Best regards,

Doug

64

EOS Bodies / Re: First Canon Mirrorless Related Patent?

« on: March 20, 2011, 03:54:29 PM »

Not that it matters much, but I have spoken of the flange back for the Micro Four Thirds system as "20 mm", whereas I see it often described as "about 20 mm" (no definitive value being cited).

There is a report from a fellow who, from a a T mount-to-Lumix DMC-G1 adapter, concludes that the Micro Four Thirds flange back is likely about 19.2 mm (recognizing that the adapter might have an offset for "safe infinity focus" built in, so perhaps the actual nominal flange back is a little larger than that).

Thus it might be that the nominal flange back for the Micro Four Thirds system is exactly half that for the Four Thirds system (which has been stated as 38.67 mm), or 19.33 mm.

Best regards,

Doug

65

Lenses / Re: List of rumored lenses

« on: March 20, 2011, 12:47:13 AM »

The EF 24-70mm has a front element large enough to be f/0.95, which makes me wonder - is the lens really as small as it can be ?

The  entrance pupil (whose diameter determines the f-number) rarely falls at the front element, but usually behind it.

As a result the front element may well need to have a greater diameter to avert vignetting.

Best regards,

Doug

66

EOS Bodies / Re: Canon Doesn't Need a Compact Camera System

« on: March 19, 2011, 09:24:28 AM »

Canon already makes quite a few "compact" cameras (my "rank" in this forum honors one), so I assume that what is being discussed here is an interchangeable lens camera system whose controlling dimensions are smaller than for the EOS family.

I am not personally interested in the availability of a reflex form in such a supposed new line, but if in fact Canon feels the need to be able to offer such, we might see indications of that in the choice of a larger back flange distance for the new system than we would otherwise expect (just as the Four Thirds system has a larger back flange distance than the Micro Four Thirds system, which is not considered to reasonably support a reflex configuration, as the Four Thirds system does).

Best regards,

Doug

67

EOS Bodies / Re: First Canon Mirrorless Related Patent?

« on: March 19, 2011, 08:42:32 AM »

Jonathan,

For further reference, in US Patent application 2011/0052185 (in which the figures seem to be identical to that shown for the Japanese application), the text discusses that the difference between the flange back of the "new" body and the flange back of the "current" [EOS] body is equal to the "thickness" of the adapter, "C", of which they then say (with respect to Figure 2):

The thickness is a
distance in the direction of the optical axis from the camera
body side installation surface 31a to the lens side installation
surface 33a

Best regards,

Doug

68

EOS Bodies / Re: First Canon Mirrorless Related Patent?

« on: March 18, 2011, 09:51:41 PM »

Hi, Jonathan,

The first time i've done the measurement between 33a and 31a, and i've found 14.2mm like you.
But if you look closely to the diagram, i suppose it will create a tiny gap of a few millimeters.

I'm not sure what you mean.

In any case, the back face of the EF lens would contact surface 33a, and face 31a would contact the face of the "new body" mount (the face that, on an actual EOS mount, corresponds to surface 33a of the adapter).

Note that in the rear view that ring 31 has two contacting ribs on its outer and inner edges, exactly as we see on the rear of an EF lens (they touch surface 33a).

The four screws seen on the rear view are "between" those ribs, actually invading them a little. It is just like that on the rear of an EF lens (at a slightly larger diameter, of course).

So i redone the calculation, suposing the adapter would "embrace" the new mount "gapless". It gives approximately 12.8~13mm

I don't follow your vision of the coupling. As I said above, as I see it, the back face of the EF lens would contact surface 33a, and face 31a would contact the face of the "new body" mount (the face that, on an actual EOS mount, corresponds to surface 33a of the adapter).

Do you not agree that the distance from surface 33a to surface 31a appears to be about 14.2 mm?

At the arbitrary scale at which I worked, the distance across the inner diameter of the front flange of the adapter (the circle that lies just inside the heads of the four cross-head screws) measured 1.981". I have no reason to believe that this face is any different than the mount on my EOS 40D (it looks exactly like the picture). There, that actual diameter is 54.0 mm.

In my workspace, the distance between surfaces 33a and 31a is 0.520". Thus, the real-size thickness of the mount would be 14.17 mm.

Certainly, the face of the "new" mount that surface 31a contacts is the reference datum from which the back flange is defined. (In the case of the EOS/EF mount, it is measured from the equivalent of surface 33a on the adapter.

    - The pin connectors on the newer mount side are the same as EF's ones, they just added 3 extra pins, so the communication protocal would be same as EF.

As I said, the patent says that with a "new" lens the protocol is different from the EOS/EF protocol, but that when an EF lens was attached, the body would use the old protocol.

Best regards,

Doug

69

EOS Bodies / Re: First Canon Mirrorless Related Patent?

« on: March 18, 2011, 09:08:31 PM »

Hi, Jonathan,

If you have seen the diagram you would immediately understand that the new mount can only support APS-C format sensor.

The rumor is that the new body series will have an 18 x 12 mm sensor. I see nothing in the patent that would conflict with that.

Just a rumor, of course.

Best regards,

Doug

70

EOS Bodies / Re: First Canon Mirrorless Related Patent?

« on: March 18, 2011, 09:05:46 PM »

Hi, Jonathan,

Hello guys !

@Dougkerr :
At the first glance your calculation is right, i've found the same result of 14.2mm when i did ot the first time too.
I've redone the calculation a second time (after the measuring the distance between the mount and the mirror in upper position on my rebel) and i've found 12.8mm (which approximately matches the adapter lenght and the spacing between mount and mirror in a rebel).

I'm not sure I follow. Are you trying to determine the flange back distance of an EOS body? That is known to be 44.00 mm.

Or were you trying to determine the thickness of the adapter from the patent drawing? I scaled it from the inside diameter of the flange ring on the front of the adapter, assuming it to be the same as the corresponding distance on an EOS mount (which is 54.0 mm).

That gives me a flange-face-to-flange-face thickness for the adapter of approximately 14.2 mm.

- The pin connectors on the newer mount side are the same as EF's ones, they just added 3 extra pins, so the communication protocal would be same as EF.

The patent says that when using the "new" lenses" the protocol would be a new one, but when an EF lens was attached through a (passive) adapter, the body would use the EF protocol.

- The pin connectors are located on the right side of the camera and vertically mounted. 

The (entire) point of the patent is that if the contact block on the new body were put at 6 o'clock, things in that area of the adapter would be very congested, so it would be desirable on the new body to have the contacts either at 12 o'clock or at 9' o'clock (as would be seen looking at the face of the camera). Both these situations are shown in figures in the patent.

- The new mount will have a 12.8mm shorter register than EF.

Not by my reckoning. How did you get that value?

PS: I apologize for my scholar english, english is not my first language.

Your English is fine!

Best regards,

Doug

71

EOS Bodies / Re: First Canon Mirrorless Related Patent?

« on: March 18, 2011, 04:39:05 PM »

The corresponding US patent application is 2011/0052185.

If we took the figure in the patent to be realistic and to scale, it would suggest that the "new" body had a back flange of about 29.8 mm. (The scale flange-to-flange thickness of the adapter seems to be about 14.2 mm; the back flange of the EF/EOS mount is 44.0 mm.)

The information I have is that the back flange for the Four Thirds format is 38.67 mm; for the Micro Four Thirds, 20.00 mm.

I have not seen a back flange speculated for the rumored Canon "EVIL" body.

There have been many recent Canon patents that suggest applicability to a mirrorless interchangeable lens camera (mostly in the area of AF technique).

Best regards,

Doug

72

Software & Accessories / Re: Thoughts on 430EX

« on: March 15, 2011, 11:57:24 AM »

Regarding the matter of multi-flash operation of the Speedlite 430EX, I posted an inquiry on another forum directed to the attention of Chuck Westfall of Canon USA, their Technical Advisor.

**********

From Doug

The Canon Speedlite 430EX is not shown by its manual as providing a multi-flash (so-called "stroboscopic") mode on a "local" basis. However, the manual (p. 27) indicates that this mode may in fact be utilized when using the flash unit as a slave in a Canon wireless flash network with all "Type A" bodies and most "Type B" ("TTL") bodies.

Is this in fact true?

From Chuck:

Yes. It requires a master unit that supports MULTI flash, such as the 580EX II, 580EX, 550EX, or the EOS 7D's built-in flash. (PS: The 60D and T3i built-in flash units can be used as master units, but they do not support MULTI flash.)

From Doug:

In another forum it was commented by one correspondent that the multi-flash ("stroboscopic") mode could be invoked (via the camera flash control menu) when the 430EX was used on an EOS 7D body, but not when used on an EOS 5D Mark II.

Is there in fact ever the opportunity to invoke multi-flash operation of the 430EX (other than perhaps as a slave unit in wireless flash network operation)? If so, in connection with which EOS bodies?

From Chuck:

The only way to achieve multi-flash operation with a 430EX or 430EX II is through use as a slave unit in a wireless flash configuration controlled by one of the eligible master units listed above.

**********

Best regards,

Doug

73

Software & Accessories / Re: Thoughts on 430EX

« on: March 14, 2011, 05:20:17 PM »

if you look at http://photonotes.org/articles/eos-flash/ and scroll down to the multi flash area, it shows the 420 and 430 as supported flashes.

I don't find anything on the page that link goes to regarding the multi-burst (stroboscopic) mode.

There is some information about using the units in a multiple-unit situation.

What am I missing here?

Best regards,

Doug

74

Software & Accessories / Re: Thoughts on 430EX

« on: March 14, 2011, 10:45:15 AM »

Well, I see I may have been barking up the wrong tree. The manual for the 430EX flash unit makes no mention of its having a multi-flash mode.

So I guess now my question becomes, "using the 430EX with the EOS 7D, can a multi-flash mode be invoked (from the Camera)? On a 5DII?"

Again, the mention of that mode in the 7D manual does not mean that it is available on any flash unit (even all those that generally can be controlled from a modern EOS body). The manual cautions that the available modes vary with the flash unit.

I should actually not have poked my nose into this at all, having neither a 430EX, an EOS 5D Mark II, nor an EOS 7D!

Carry on.

Best regards,

Doug

75

Software & Accessories / Re: Thoughts on 430EX

« on: March 14, 2011, 09:43:17 AM »

The 5DII does not have this feature.

Are you sure that multi mode (a feature of the flash unit, not of the camera) cannot be invoked from the 5DII?

The manual for the 5DII shows (p. 105, item 3) the ability to set the flash mode on a 430EX (multi mode is one of those). Unlike the 7D manual, it doesn't mention what all the choices are at all. But I would have no reason that the choices are somehow more limited when being set from the 5DII than from the 7D.

Best regards,

Doug