Messages

61

EOS Bodies / Re: Dynamic Range vs. Exposure Range, and why the difference matters

« on: March 13, 2013, 08:56:37 AM »

"Dynamic range is the range of signal that a sensor can record" is an odd duck. Introducing sensors with different capabilities doesn't change the luminance DR of the room in which I'm sitting. Introducing microphones with different capabilities doesn't change the acoustic DR of my guitar.

From a sensor's perspective, sure: DR is the range of signal it can record.

I'm not a sensor (even if maybe my eyes and ears and nerves are).

It seems to me the most appropriate use for the term from a photographer's perspective is the widest range of useful brightness values I can expect to reproduce with my cameras. I don't care about ideal sensors in the real world, and it serves me little purpose to introduce one term to use in the ideal and a different term to use in the actual.

62

Software & Accessories / Re: 1d X "silent" mode.

« on: March 12, 2013, 12:09:02 PM »

Agreed - the shutter needed to be robust to move at 12 fps and last 400K cycles, I suspect they made it as quiet as they could...

I wouldn't think the shutter drove the design as much as the mirror mechanism. Shutters have been capable of opening and closing over the frame at 1/8000 sec.

You're right, of course.  I meant mirror (which also has to flip at 12 fps).  Although the shutter makes a slight contribution to the noise, most of it comes from the mirror.

So in theory, mirror locked up, live view shooting could be a kind of silent mode?

Sure, if you're willing to forgo the bulk of the AF functionality.

63

Software & Accessories / Re: 1d X "silent" mode.

« on: March 12, 2013, 11:54:01 AM »

Agreed - the shutter needed to be robust to move at 12 fps and last 400K cycles, I suspect they made it as quiet as they could...

I wouldn't think the shutter drove the design as much as the mirror mechanism. Shutters have been capable of opening and closing over the frame at 1/8000 sec.

You're right, of course.  I meant mirror (which also has to flip at 12 fps).

Yep, it's a heavy inertial component. I've never had one fail (always tend to replace cameras before about 70,000 actuations). I wonder whether the drive motor goes or whether parts actually break.

64

Software & Accessories / Re: 1d X "silent" mode.

« on: March 12, 2013, 11:47:36 AM »

Agreed - the shutter needed to be robust to move at 12 fps and last 400K cycles, I suspect they made it as quiet as they could...

I wouldn't think the shutter drove the design as much as the mirror mechanism. Dual curtain shutters have long been capable of opening and closing over the frame in 1/8000 sec (1/10000 on some mid format models, which is impressive considering the increased coverage).

65

Landscape / Re: Landscape photography from around the world, shot on Canon

« on: March 11, 2013, 01:15:39 PM »

beautiful work

66

Lenses / Re: Bridge not sharp - why?

« on: March 11, 2013, 10:08:14 AM »

In reality it's likely a combination of things:
-Motion smearing at the camera level
-Wind/Atmospheric effects
-Wavefront error

That fact that you got good results sometimes suggests an environmental culprit, not faulty equipment (unless it's failing sporadically).

Either the bridge is moving slightly or the platform you're standing on is moving.  Any civil engineers on the forum?

Can the bridge move? Yes. But if it's moving, the camera probably isn't still.

btw, is this the Bixby Bridge?

The columns are different (more ornamental), plus he said it's in oregon.

67

Software & Accessories / Re: Is this support setup good?

« on: March 06, 2013, 11:45:23 AM »

Gitzo: Material - "carbon fiber 6X"

The engineer in me wishes they'd be more forthcoming with the materials used. Which fiber? Which resin system?

I think I read somewhere that the tubes are 3mm thick. 6 layers, so they're what, .020" thick fibers? Or do they have an exceptionally low fiber volume?

I guess at the end of the day it doesn't matter provided it exceeds the spec loads, but I always get a little... incredulous at the blanket use of the term "carbon fiber."

68

EOS Bodies / Re: Pixel density, resolution, and diffraction in cameras like the 7D II

« on: March 06, 2013, 11:14:59 AM »

I believe that an "oversampling" sensor, i.e. one in which sensel density is higher than what mandated for the expected end-to-end system resolution would make problems easier if we could have it at no other cost.

That's essentially what we have with 2MP video from these 20+MP still sensors, right?

69

Lenses / Re: Addicted to dof

« on: March 06, 2013, 08:38:59 AM »

The 85L has more OOF Blur at the same apertures compared to other lenses.... this is key for you.

Take a look at this: http://www.the-digital-picture.com/Reviews/Sigma-85mm-f-1.4-EX-DG-HSM-Lens-Review.aspx

The 4th pic down of his daughter holding a iron fence... hover over the different F values and you will see that F2, the EF85L has almost as much blur as the Sigma does at F1.4.  And we know Sigma is better than the EF 85 F/1.8...  You will have 2-3 virtual apertures left with the 85L (or should I say levels) to blur out the background more.

It is a very sharp lens even wide open. You will lose some AF speed but then are you also addicted to AF speed?

I would own one if I made money off this hobby...

So....K-amps...why is the Canon so much more "bokehlicious" at a given aperture, focal length and distance with similar (?) aperture blades? I recently read somewhere that there is another factor ( a revelation actually...that I was unaware of), affecting Bokeh....but I can' seem to recall what it was  My memory fails me at times...
Nice article reference BTW!...I missed that one.

Blur quality isn't necessarily a function of the shallowness of the DOF. Generally, the shape of the aperture plays a major role. The better the iris approximates a circle, the rounder the out-of-focus spots tend to be. Hard lines in OOF can look jarring, which is why for example the OOF areas look 'better' with a 50mm/1.2 (8 blades) than with a 50mm/1.8 (5 blades), even with the former stopped down to match depth of field.

There are some exotic lenses with as many as 20 blades.

70

EOS Bodies / Re: Pixel density, resolution, and diffraction in cameras like the 7D II

« on: March 06, 2013, 08:35:58 AM »

Now, if all thread contributors agree that noise and hard-to-characterize PSF kernels are the main practical obstacles to deconvolution (along with the sampling process and color filtering), this thread can be more valuable to the reader.

If that's what you're going for, perhaps a definition of all acronyms used would be of use. This thread rapidly went from fairly straightforward to deeply convoluted (pun intended) and jargon-heavy.

I think I have an approximate understanding of the current line of discussion, however I'm not sure how it relates back to the OP (seems to have shifted from whether it makes sense to have a higher spacial resolution sensor in a diffraction-limited case to whether one can always algorithmically fix images which may have a host of problems).

71

Lenses / Re: EF 600mm f/4L IS II USM or EF 400mm f/2.8L IS II USM

« on: March 05, 2013, 02:04:08 PM »

tell me more about this sleight of hand expert and where I might find one

That was tongue-in-cheek.

72

Lenses / Re: EF 600mm f/4L IS II USM or EF 400mm f/2.8L IS II USM

« on: March 05, 2013, 08:34:55 AM »

If you're worried about reach, get the 1.4X teleconverter too, and then you'll have effectively a 560mm f/4 lens, for when you need the extra length.

Also order a sleight of hand expert to add or remove the TC on an as needed basis, quickly enough to not miss the intended action

73

Landscape / Re: Shooting locations in O'ahu.

« on: March 04, 2013, 02:00:28 PM »

I headed to Honolulu on business during the first week of February.

I hope I'm not too late:

Take Tantalus Drive up to Puu Ualokua park. You can see from diamond head (past it, actually) all clear over to the far side of pearl harbor.

74

Landscape / Re: Post Your National Park Photos

« on: March 04, 2013, 01:47:32 PM »

From what is quite possibly my favorite national park (although there are numerous parks I'll never be able to visit), Plitvička Jezera.

75

Lenses / Re: Best lens for baby portraits?

« on: March 04, 2013, 09:08:37 AM »

We're expecting a baby soon, and I thought it would be fun to rent a nice lens to take some early portraits. I assume a fast prime L lens makes sense, but what focal length? Any specific lens rental companies to recommend? Thanks.

I absolutely agree with the 50/1.4 on full frame suggestions, meaning the you would need something a little wider to accomplish the same. A zoom like the 17-40 would be functional from a framing standpoint, but less pleasing due to the increased DOF.

The ability to sit right up close with your baby and still frame him/her is invaluable. When I had to drop my 5D2 at the canon service center and used a crop camera, I was constantly dismayed by the need to either back up and have him be less responsive to daddy-right-here-making-me-laugh or sacrifice framing.

My son walks now, so I shoot a mixture of 50mm (when I'm willing to chase him around for close framing) and 24-70mm (when I'd rather show him in the environment).

Word of advise: enjoy the time you have when you can place him in nice light and he actually stays there
Have fun and good luck.