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Messages - Aglet

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Reviews / Re: Pentax 645z Review
« on: Today at 08:22:49 PM »
I've never hand-on mf body before. To me, this body looks  :-\
It's a bit heavy but it's actually quite nice handling without a tripod

Reviews / Re: Pentax 645z Review
« on: Today at 08:21:29 PM »

Third Party Manufacturers / Re: DXO uh-oh?
« on: July 29, 2014, 02:49:49 PM »
Thanks for your posts.

There's a few of us here who will heartily agree with most of what you said.  I was a Canon fan until the superior raw files from a $400 Nikon consumer body blew my 5D2 into the weeds!  Well, at that time I was already a Canon fan in decline and searching for better options as I'd realized the 5D2, so hyped by fanboys, was a bit of a turd with very noisy low ISO raw files and a tendency to underexpose; or at least the one I had was.

Your example of the model, whose arm was in deep shadow, and looking like it has a bad rash because of the read noise, is a good one.
When pushing the limits, sure, there are plenty of "work-arounds" to make Canon cameras able to produce the desired shot.  People doing that seem to be forgetting they're compensating for under-performing hardware!  Poor hardware IS a good way to improve your skills as a photographer, as you have to be extra creative to overcome the limitations of your tools.  Reduce the limitations placed on your shooting by those under-performing (Canon) tools and you're now free to benefit from a range of other advantages like less setup time, less time in post, more freedom and flexibility in lighting and exposure, etc.

Ardent fanboys will continue to argue that technique matters more.  It sure does, especially when you chose to use gear with more limitations for certain kinds of shots.

As for the lens argument some make, sure, Canon has some excellent lenses.  But there's also plenty of good glass for Nikon and no matter how bad the Nikon lens may be, it still doesn't change the read noise issue.

My D800/e are my favorite bodies for my kind of shooting yet and I only wish I would have not been so prejudiced in the past so I could have benefitted from using the advantages of other camera brands much earlier.  I haven't purchased a new Canon camera for years now.  But I have purchased Nikon, Pentax, Fuji and Olympus and have enjoyed the benefits they all bring while none of them are as limited by FPN and read-noise issues as Canon. 
Despite the sales and marketing success, Canon is now the underdog, and I actually hope they can perform some sort of a comeback miracle; it might give me one more tool to use.

EDIT:  BTW, I would not be surprised if Nero isn't already pondering and composing an acrid response to your posts.  ;)

Technical Support / Re: Flaws on the rear element
« on: July 29, 2014, 01:17:29 AM »
I went thru 4 of those 100mm macros until I found one that didn't have a lot of those sorts of flaws apparent on the internal lens elements.
Just looking into the back end of them, pointing towards the sun, I could see many such pinpoint flaws, more than could be counted, which appeared like coating flaws.  Not sure if tiny bubbles as MSP suggests.  They appeared considerably larger than the dust particles.
Turned out that the lens I kept was the oldest, most worn looking one I got for the cheapest from another photog.  it had better contrast than the other 3 and I still have it.

Third Party Manufacturers / Re: DXO uh-oh?
« on: July 25, 2014, 02:09:17 AM »
Well, the interesting part of the test data is showing the d810 has a real ISO 50 (47) available, labelled as 64 and 32 extended.

The SNR at the new low ISO is now pushed down to .008% gray scale, a number only attained by Pentax' K5ii series at its measured ISO of 68 (80) until now.  The pixel-level DR is increased to 13.67 in the d810 vs 13.59 in the K5ii

I'll keep my old d800e; at ISO 12,800 and lower, it has slightly cleaner shadows than the new d810 at all matching ISO settings.  Not by much but it seems to show a slight compromise was made to the 810's sensor system to improve the measured spec in one(some) area at the expense of others.

So IMO for the D810 it's 2 steps fwd (iso 64 and 25,600) and 1 step back (increased shadow noise at ISOs 100 thru 12,800)
it does have a plethora of minor improvements tho, enough to make it an appealing upgrade option if you only have a regular d800 or lesser FF body.
i'd really like to make use of the electronic 1st curtain shutter and the better balanced mirror-shutter system for even more easily attained maximum sharpness.  Other improvements. e.g. fps and AF options and better battery life, bring it a little closer to being an all-around useful camera, not just a landscape monster.

Third Party Manufacturers / Re: Anyone own both Canon and Nikon
« on: July 22, 2014, 03:40:48 AM »

OTOH, my D800s I find very comfortable to hold and carry for long periods, never use any kind of strap, they balance nicely with mid-weight zooms and AF (landscape) with great precision at every point even in very low light and low contrast subjects.
I never used a D700 but do hear plenty of raves about it.  FWIW, out of over 80 DSLR camera bodies (some duplicates of course) I've used in my database, I find the d800 to be the most enjoyable with the d5100/5300 being my preferred consumer crop bodies.  7D, 40-50-60D, 5D2 and 5D3 I also like the fit and feel of but I sometimes need to really stretch the limits of a raw file and the Nik's help me out there better than the Canon goods can.

I also regularly use various Pentax bodies and enjoy the fit and feel of them but they have a few minor ergonomic issues and poor placement of some controls that get in the way at times.

The only bad feel, hurt my hands cameras I've ever grabbed are the D7x00 and D6x0 series Nikons; I find them just plain aweful.  Bought a second d800 because the d600 was such an uncomfortable thing to use as a 2nd body.

Lenses / Re: Something with 50mm L lens that make it different
« on: July 22, 2014, 03:27:00 AM »
I'll take a shot at that 50mm challenge but it sure has a lot like pickin' fly-specs out of a pepper pile.

My best guesses using very limited clues in the images:

Canon 50/1.4 shots:  girl in hallway, dog, doll with book, girl bottom left
Canon 50/1.2 L shots:  leaf in centre, B&W whisk, blonde girl in dry grass, girl bottom right

unspecified shots, like the closeups in the upper and middle R side or top left could be 50/1.2 L or anything really.

EDIT:  forgot to add, that's from the untitled 2 tile.

the untitled 1 tile only the girl on the escalator strikes me as likely a 50/1.4 lens shot, maybe the one below it as well.
 all the others don't show enough info to differentiate much so I'll just guess:

50/1.2; barley field, horse muzzle, guitar, kid 2nd from top on right,
50/1.4; roses, girl w umbrella top left, possibly the others not stated above.

score me, PBD. :D

Third Party Manufacturers / Re: Anyone own both Canon and Nikon
« on: July 17, 2014, 01:32:17 AM »
As usual, this query garners fervent rhetoric from those faithfully wedded to Canon. :)

I just re-read the entire thread and didn't see any "fervent rhetoric;"  would you mind pointing it out?  What I see are measured, thoughtful responses about different offerings.

Hi orangutan, just look at the post from Aglet.  You will soon see plentiful amounts of fervour.   :)
but I'm so glad he has pointed out all that banding in my images. Just imaging all this time all these photos and I've never noticed it. I must be a rubbish photographer. I must rush out and become a fervently passionate Nikon owner.

banding's for birds ;)
ease off on the unsharp mask too, halos are for angels. ;D /dig
actually, I like some of the shots you've posted.

EOS Bodies / Re: Eos7D mk2, How EXCITED will you be if . . .?
« on: July 16, 2014, 03:38:05 PM »
What's your evidence for that?  Current Foveon sensors are crap at high ISO.  For example, the LL review of the DP2M cites 'poor IQ above ISO 400...with current Canon sensors, ISO 800 isn't even 'high ISO'.

Old info.
Latest Sigma Quattro has made significant ISO performance improvements, especially considering how few iterations of such a sensor have been produced.
edit:  arghhh.. was just looking at samples of it and, despite better ISO performance above base, it's got far too much vertical banding for my liking.  Unfortunate, as detail is crisp and color on object edges is more like I'd prefer.

Seems like your understanding of these concepts is about as astute as your comprehension of the sensor design for DPAF, i.e. very poor:

Why do you punctuate your flawed argument with an disparaging personal remark?
seems your understanding of acceptable social behavior may be comparably flawed

EOS Bodies / Re: DSLR ? - thinking out loud ....
« on: July 13, 2014, 02:01:57 PM »
As for the DR and color, that's precisely why I want an EVF: I want to compose using what the sensor can see, so I have a better idea of the final image.  This is another plus for EVF.

So you want a better idea of what the in-camera JPG conversion will look like, if displayed on an uncalibrated monitor with low resolution and a poor color gamut?  Sounds like a big minus for EVF to me, particularly for anyone who shoots RAW...

I'm surprised, you don't usually make bad arguments.  You have invoked the "it is thus and ever shall be" argument.  I'm saying I want an improved Live View through the viewfinder, and I believe it's achievable in the next few years.  I'm not saying current EVF is adequate.
You are apparently assuming display technology will improve while image capture technology remains stagnant...sorry, but that's the bad argument here.  Both are improving (and will likely continue to) in parallel, and given the already large lead that image capture has in terms of bit depth, it's highly unlikely that you'll ever be able to look through an EVF and 'see what the sensor sees'.

You're being a bit too literalistic.  If you read the context of my post, it was in response to the statement that EVF is inferior because it cannot show what the human eye sees.  The intent of my response was to say that such a position is irrelevant because the human eye can't see which parts of a scene will be clipped, or which parts of a scene will be in focus, etc.  An important reason for  Live View (and EVF) is to have the sensor give you helpful information to capture the data you will need for post-processing.  Beyond that, it need only be "true" enough to allow the creative aspects of composition.

As a side note: you are correct that sensor tech will continue to improve; however, there's no reason a high-end EVF can't have a couple of dials to spin through the range of what it sees.  As an analogy consider flight simulators: for those who don't have surround monitor sets, there are controls to "turn your head" and look out the side windows.  An EVF may not present all data at once, but can still present it.
there are no significant shortcomings on today's better EVFs to prevent them from allowing composition control in most circumstances while also being able to provide a great deal of extra information simultaneously that current OVF systems do not.

Landscape / Re: Beautiful sunsets
« on: July 13, 2014, 01:48:24 PM »

Sunset at the canyons

Nice shot.
personally, I find it frustrating when jet contrails mess up the sky on a nice scene like this but it's getting harder to get away from them.

EOS Bodies / Re: DSLR ? - thinking out loud ....
« on: July 13, 2014, 03:25:09 AM »
It seems some comments are coming from people who haven't used a MILC with a decent EVF.

Higher end mirrorless and EVFs are at the point NOW where they are comparable to many consumer/prosumer DSLRs in performance in most conditions, including low light.  Give them another year or 2 and they will likely be on par with their mirror-flapping counterparts. .. And then they'll exceed them.

The EVFs in current Olympus and Fuji cameras are impressive and I'm sure Sony's are comparable as well.
They're OLED, so have very good dynamic range and color gamut.  Lag exists but in some of them, like the Fuji XT1, it's quite minimal in decent light and not bad in low light either.

I attended an event last nite, turned out to be a dim and poorly lit club.  I wanted a compact but reasonably capable camera with me.  So I grabbed an old Fuji XE1 over a Pentax Q because I wanted an EVF.  Unfortunately, I grabbed one I'd just bought used so I had not yet set it up the way I liked.  As it is, I barely use the XE1 enough to be partly atuned to it so there were plenty of shots I could have done better using more familiar gear.  It didn't matter, this was not a job.
I used the 27mm f/2.8 pancake prime on it; very light, small and discreet compared to any sort of DSLR.

The XE1 is slightly older tech already, and it still performed better than I expected and certainly was no worse to use than a small pentamirror OVF in a consumer DSLR.  Actually, it was no problem framing and composing images in low light where I had to use iso 3200 or 6400 at 1/15s and f/4.

AF performance was not great but it was still possible to do a good manual focus using the magnified live view in the EVF fairly quickly when needed.  I don't think many consumer grade DSLRs would have had much better AF performance on the dark and low contrast targets I shot anyway but they may have been a bit quicker for focus and recompose or some of the moving targets.

Third Party Manufacturers / Re: Nikon's D800E 30% sharper than D800
« on: July 10, 2014, 02:56:40 AM »
OK, I trust you guys know your optics and related math much better than I do.  I'm just trying to figure something out here that's not quite making sense to me yet so if you care to indulge following the path I'm on with this, please tell me which step I slipped on.

I'll use round numbers for convenience but referring to the numbers jrista provided on a previous page.

Step 1:

- A digital image sensor (e.g. D800e) with pixels that are 5 microns square = 100 lp/mm physical sensor resolution with no AA filter.
I presume with whatever kind of algorithm is used, it is possible to read alternating rows of pixels, if they are properly stimulated, such that it would be possible to electronically extract the maximum of 100 lp/mm from this sensor.  If this were a monochrome rather than Bayer sensor then likely even simpler.

The resulting contrast ratio, if one were to stimulate alternating rows of pixels with high and low (dark) intensities would depend on the spot size of the illumination and how it was modulated during the raster.

Let's cheat a little bit, for fun.
I'm thinking if a visible light laser beam could be focused to about 1 micron, then rastered across the sensor in perfect geometric alignment and modulated such that the beam was ON only while the edge of its spot fringe was entirely located within a given pixel (row) such that no appreciable amount of that light were to enter an adjacent pixel (row), then the resulting contrast ratio would be quite high as there would be no bleed-over to the pixels in the dark row resulting from the fuzzy fringe of the spot.
This would be cheating because it would not be a perfect square wave function but would required a reduced ON time vs the normal 50% ON to 50% OFF of a square wave.

Thus we have applied a pattern of light and dark lines to the sensor synchronized with the sensor's physical pixel layout such that every second pixel is illuminated and alternating ones are dark.
We get 100 lp/mm equivalent signal from the sensor.  Still, we may have slightly less than perfect maximum (MTF) contrast ratio between rows but it's likely to be much higher than the typical 50% MTF standard. 

If we were to instead modulate the light spot (without cheating) so that it was turned ON and OFF as its center crossed the boundary from one (row) of pixel(s) to the next, then that will have an equivalent contrast ratio you could calculate at about 5:1.

Are there any errors in this hypothetical assumption so far?

Step 2:

- we have some lens that is capable of resolving 150 lp/mm at an MTF of 50% as measured on some optical bench...
This same lens should have a better than 50% MTF result if it were resolving a test target at 100 lp/mm.

Any error in step 2?

Step 3:

- we take the lens in step 2 and use it to focus a 100 lp/mm image onto the sensor in Step 1.  (We can use monochrome light if we have to minimize focus errors from CA)
We must now carefully align the focused image to the pixels on the sensor so that the middle of the bright line corresponds to the middle of a pixel (row) with the middle of the dark line aligned to the middle of the next pixel (row).  This should yield the maximum readable contrast ratio from the electronic sensor.
IF the alignment is PERFECT then the contrast ratio should still be a reasonably good number.  As the alignment shifts away from perfect the resulting contrast ratio will drop to a low of 1:1 (2.5 micron shift) for adjacent pixels which means no discernible contrast at all.

Are there any errors in step 3?


If there were no errors in the 3 steps above then it is possible for a lens and sensor combination to resolve the physical maximum lp/mm of the sensor if the lens has a sufficiently higher resolving power in at least the ideal circumstance described.

Add angular and positional misalignments and mismatches in spatial frequency and you'll get aliasing and all manner of things that throw the above out the window and the math explained in this thread describes the system behavior.

is the conclusion correct within the limitations stipulated?

I'm not yet sure what Aglet's angle is:

here it's just dark humor in the form of satire.. for the sake of balance.
Hard to follow a good bit like unfocused's.

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