-hh wrote:
On Monday, September 10, 2018 at 5:31:57 PM UTC-4, Savageduck wrote:
-hh wrote:
On Monday, September 10, 2018 at 10:58:31 AM UTC-4, Savageduck wrote:
-hh wrote:
On Monday, September 10, 2018 at 12:38:17 AM UTC-4, Savageduck wrote:
-hh said:

wrote:
The SLR was a great idea when needed to have a seperate path for
viewing and film exposure, but with digital, the sensor can be the
viewing as well as the recording medium so perhaps less need for a
separate path via flip up mirror ?

It depends.

First, to drive two digital outputs (display + data recording) requires
the product to have more power ... both computational power and literal
power (battery).

...and so the MILCs which work do just that.

Understood, but the devil is in the details. The problem
is that the classical pro-MILC is that this is part of what
allows a MILC to be smaller...but their higher power demands
works against this. As such, it isn't a "gimme".

WTF is a "classical pro-MILC"?

I'm referring to the classical arguments that are advocating
for MILC hardware.

You don't seem to have an understanding of the capabilities
of any MILC.

Oh, I know that I'm not up-to-date on these new consumer centric
products that cost under $10K - - but that doesn't mean that I
don't know the engineering principles or application ... indeed,
these are where I've taken the conversation. FYI, the first
digital MILC that I've personally spec'd/bought/used was more
than a decade ago.

Knowing the engineering principles, or application, and actually using and
understanding the current generation of MILC cameras are two different
things. You had better believe ...

Oh, please: the improvements have been incremental, as the base
technology hasn't changed: it is still "mirrorless".


If the first MILC you "personally spec'd/bought/used" was more than a
decade ago, you have no idea of the current generation of MILCs which are
are leaps ahead of what was available less than two years ago.

That's a good 'Motherhood' statement for technology in general, but it
actually depends on what's important to your photographic needs.

For example, the ancient MILC I'd bought still outperforms your shiny new
camera on certain metrics ... and do note that these were the factors which
our purchase decision was based on.

Case in point, on shutter speed: how much faster than 2 μs is your camera?

No, that's not a typo: I did say "μs" to indicate microseconds (10E-6),
and 2 μs is 1/500,000sec.

Now I am curious, what was this pioneering MILC with astonishing shutter
speed (that most photographers would probably never use).

Of my cameras the X-T2 has a fastest mechanical shutter speed of 1/8000,
and electronic shutter speed of 1/32,000. Other than the occasional
equipment experiment I have never needed to push to either extreme.


One net effect from ditching the mirror and shutter is that the
camera's now a staring system rather than a metered system. In
digital incarnations of staring systems, the performance of the
data management system becomes quite significant ... and for high
performance, high bandwidth which means that it becomes quite
computationally expensive.

WTF do you mean "staring system"?

It means you're trying to lecture the wrong person.

Apparently.

MILCs meter off the sensor, and have processors more than capable of
handling the data fed to/through them. The current Fujifilm CPU is a
powerful multi-core processor.

Nice ad copy -- where's the manufacturer's published specifications?


Similarly, inclusion of a second image path in parallel for a
so-called "real-time" viewfinder also incurs additional data bus
bandwidth & demands on computational power.

A second image path in parallel sound more like a traditional SLR/DSLR
than any MILC.

Not really, since it is parallel in real time and a flopping reflex mirror doesn't do
that.

But because even a blind squirrel does occasionally find a nut, I will give you
a partial credit, since a suitably parallelized approach has been featured in
SLR's, although it never was particularly popular. This was the use of the
Pellicle Mirror in lieu of a reflex mirror, such as in the Canon EOS RT.


There is no free lunch.

Not even for SLR/DSLRs.

Of course not.


Second, an LCD display isn’t always a good thing to view through, as
there’s lag for example, which degrades tracking performance of moving
targets.
The classical optical path operates at 186,000 miles/second, which is a
few femtoseconds, whereas the digital display replacement requires
photon to electron reception on the CCD, followed by a data read, then
data transmit, data processing, another transmit, & finally to be
redisplayed. Even with current technology still takes bunches of
milliseconds...and try to see where this metric even listed in product
reviews: it’s already been found that in 3D VR simulators this delay
often causes nausea in human subject research volunteers (and thus,
limits/affects experimental designs).

What are you trying to say? We are not discussing 3D VR simulators.

The 3D VR sim stuff has been published in Open Literature.
Other stuff hasn't been published, so it can't be discussed in this forum.

So what?

The issue of temporal lag doesn't typically manifest itself today
in relatively benign (quasi-static) photographic shooting situations

So...

... but that doesn't mean that it doesn't exist, nor that it will
remain unimportant.

The more that the engagement timeline accelerates (faster subject
movement & system track/panning, etc), the more critical the
processing time becomes in system performance, as well as the more
that the temporal mis-synchronization between sensory inputs will
mess up the human.

That's why I said "what's the published performance data?".

...and cameras such as the X-H1, X-T2, and the new X-T3 have no
problem with faster subject movement, & system track/panning, etc..

That you know of.

That I know of, because I use one.

Personal Anecdote.

So, sometimes personal experience counts.

What does the OEM's detailed technical specifications say?
No, not their mere ad copy for consumers...


Beyond the published specs which are freely available from various review
sites, I am not privy to "detailed technical specifications" after all I am
but a consumer.

Try one some day.

Oh, that may become quite likely, as I got a 'headhunter' call last
Friday asking about my availability later this year to take over
part of a project that's working in this area. Apparently, they
really liked my suggestion that they could just buy $50K worth of
these current commercial products off-the-shelf with which to do
some surrogate tests could get a quick reality check on their
performance requirements and chop a year off of their schedule,
and they're looking at me to go do just that.

You better go ahead and take the job.

We'll see. I'm currently managing a group of PhDs in a human subject
research lab and next year's work here is looking at [recused].

Busy, busy, busy.

Have you tried one of the latest MILCs such as the X-T2, X-H1, or the
Sony a7III? ...and then there are the latest releases such as the X-T3
where there is no blackout even at 30fps.

This isn't about blackout.

MILCs today such as my X-T2 have EVF refresh rate of 100 fps.

Sounds good from an advertising copy perspective, but this isn't
refresh rate either. The question is just how many milliseconds
worth of processing delay is there from data capture of frame N
to the actual display of frame N on the EVF?

The EVF refresh rate is 100 fps. Display time lag is 0.005 sec.

And here's an example of how advertising copy allows people to be deceived.

Yes, the display lag time of the EVF hardware is a factor in the overall
temporal chain - - but it isn't the _only_ factor. The only thing that this
5ms "spec" is actually telling you is that once the EVF finally gets a frame
to be displayed, it takes that hardware an additional 50ms to make it appear
on its screen.

....and that matters not one bit when it comes to actually using whichever
camera the photographer, including yours truly, is using since I don't
usually carry a full test bench with me on any shoot. I suspect that it
doesn't matter that much to you when it comes to your photography.

That doesn't tell you how much time went by from the time that the photons hit
the CCD/CMOS receptor to be collected.

From an engineering standpoint, the receptor is a time-sampled period used
to integrate the signal (thereby forming a discrete 'image'), which then gets
bussed to the CPU for processing - - and resampling to the smaller EVF - -
before it gets sent to the EVF for display.

....and I have yet to have that "time-sampled period" be critical in any
digital camera I have used.

The KISS net result of all of this is that the data in the EVF is always several
data frames old .. and the key technical data performance question is *HOW*
many frames old is it? Again, what does the OEM's technical data sheet say?

Again I do not have that data sheet.


You don't know.

...and your experience with these cameras, other than an opinion you hold,
is what?

Besides a couple of Engineering degrees, professional experience, a bunch
of stuff that I'm not authorized to talk about, and even a job offer to research,
test & invariably write the technical performance specifications for a new piece
of digital imaging hardware that's looking to use the likes of your shiny camera
as just a cheap test mule? Oh, utterly nothing, of course! /S

That's nice.

And no, it isn't 1/100 = 10msec, because there can be multiple
frames' in-process in the buffers before it finally gets to be
the frame that's pushed out to the EVF display.

...and when shooting multiple frames in CH/CL, or an AE bracket (3-9
frames), or any of the other bracket options, the buffer clears very
quickly after writing to the SD card.

There's still a buffer. What's the OEM technical specifications say it is?

As to the image in the EVF display, there is no perceptible delay, not even
as much as I have experienced with my D300S and its mirror blackout.

Well, on human perception & performance, the biology of the human nervous
system is such that we live ~250ms in the past.



As I said, the Devil is in the Details.

Which you have not examined, just opined on.

No, I've merely shared what I can, and have shown some principles of physics
that you can't violate, even if the advertising copy suggests otherwise.


Similarly, in pragmatic field use, one classical photography principle
is to put the sun at your back ... but this means that the sun is now
positioned so that it will illuminate your
LCD display & degrade its readability unless it’s shaded - such as
being designed with the same eyepiece cup as classical SLR’s. FYI,
shooting during Golden Hours results
in a much lower sun angle which can accentuate this as a problem...the
outcome is that the photographer needs to have a big fat head to make
shade to see what he’s framing.

You do understand that MILCs have an EVF which is used in much the same
way the traditional OVF is used on a DSLR.

I've not checked specific products, but that's precisely why I mentioned
the eyepiece in the above: that's the only simple way to assure that the
electronic VF won't get messed up by sun ... although there's still also
other factors.

Of course you haven't checked specific products, it doesn't sound as
if you have ever considered any MILC. Just remember, an MILC is not
a phone camera, or a P&S/compact without an eye level VF.

Except that there's no firm requirement that a MILC must contain
an eye level viewfinder. And given how commonplace for there to
be a rear screen too does illustrate that the OEMs do expect their
users to not always employ the eye level one. As such, my comments
about sun angle & display washout aren't irrelevant.


I would have thought by now you would have grasped that I have been
referring to MILCs which have an eye-level EVF.

Oh, I've certainly grasped that you're talking within a very narrow box.
In several ways more than you realize, though.

[...]


My next camera upgrade will probably be to upgrade my underwater
camera system, and something mirrorless should be more compact
form factor than the ~8 year old Canon 7D dSLR with its UW housing
that I'm currently using.

Then you have to buy whatever meets your needs.

But of course. The main issue that I had with the current
dSLR solution was that at the time (2010) there wasn't any
support for ultra-wide angle lenses for any of the P&S or
even the what was then-emerging 4/3rds systems in an UW setup.
My benchmark was to match the Nikkor 15mm from my Nikonos V;
the closest I could get to was a 24mm equivalent, which is
a huge difference in UW.


How wide do you want to go?

See above:
"My benchmark was to match the Nikkor 15mm from my Nikonos V..."

In my bag of Fujifilm lenses I have an XF14mm f/2.8, and an XF16mm f/1.4.

Also available for my cameras is a Zeiss Touit 12mm f/2 (AF) and various
Samyang, and Rokinon 12, 10, & 8mm manual focus lenses, and the Loawa 9mm
f/2.8 Zero-D

Appropriate focal length lenses is only the first step of at least three.

You also need:

2. the UW camera housing for the body. If it isn't sold, you're stuck.

Yup.

3. the UW lens port/dome for that body+lens combination. If this isn't sold,
then you have to pick another lens.

Yup

For example, the UW housing manufacturer with the broadest product line
is Ikelite. So feel free to show us where they sell a body for your MILC model.

Then, go he

https://www.ikelite.com/pages/lens-port-charts

...and identify just what lenses are supported.

For my particular camera Ikelite does not build a housing. However,
Aquatech, Nauticam, Subal, and Meikon do. Perhaps not Ikelite, but capable.

https://aquatech.net/collections/fujifilm/products/atb-xt2-camera-water-housing-kit

https://www.nauticam.com/collections/mirrorless-il-camera-housings/products/na-xt2-housing-for-fujifilm-x-t2-camera

http://subal.com

https://meikon.com.hk/collections/underwater-waterproof-camera-housing-case-for-fujifilm/products/fujifilm-x-t2-40m-130ft-underwater-camera-housing-kit-with-seafrogs-dry-dome-port-v-1

FYI, if you come up empty (no suitable product exists), then welcome to my
world ... feel free to provide alternate solution recommendations.

Alternatives provided above.



--
Regards,
Savageduck