September 01, 2014, 07:29:04 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - Aglet

Pages: 1 ... 3 4 [5] 6 7 ... 64
61
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.

62
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?


Conclusion:

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?

63
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.

64
:'( Goodbye my dear 5d mk III . ..Don't let the door hit you in the A$$.  :o

I hear ya, man.
I was married to her older half-sister, 5d2, and divorced her.
5d2 snored a lot and filled my nights and even my blue-sky-days with her infernal noise. 
I even tried to seek shelter in the darker parts of town but the noise followed wherever I went.

I think those 5D girls sure looked voluptuous but mine was also hard for me to live with.  I think they came from an unrefined family;  I heard their mother was a Rebel and 5d2's father was a point-n-shoot who didn't stick around but a year or so.  I don't know who planted the seed for 5d3.

While feeling a bit lonely for a pleasant and reliable companion i saw a mail-order ad for a new bride in the form of a petite d5100.  When she arrived I discovered she didn't speak my language very well but we soon learned how to communicate and she rarely needed to be corrected.  She is very well behaved and, while not terribly sophisticated, always tries hard and put out her best efforts.  If she has a flaw it's maybe that one leg is a bit shorter than the other because whenever I line up a perfect horizon in her viewfinder the picture comes out a bit tilted...  We learn to compensate.

I soon discover she has lots of interesting relatives and within a year I find I've sponsored 5 more of her family and much of their estate now reside with me and we all play together and have lots of fun.  They were even very accepting of my fostering Pentax, Fuji and Olympus underdogs.  A few elderly Canon family members remain as well as they're just not worth moving to another home and they still occasionally can do some useful chores.

65
Third Party Manufacturers / Re: Anyone own both Canon and Nikon
« on: July 08, 2014, 01:44:31 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.
yup, missed that on my proof-read
should be
Usually this query garners fervent rhetoric...
tho it's still early and the original version could turn out correct after a while. ;)

66
Third Party Manufacturers / Re: Nikon's D800E 30% sharper than D800
« on: July 07, 2014, 09:54:59 PM »
The resolving power of an optical system (i.e. a whole camera with lens and sensor) is limited by the resolving power if the least capable component. If that is the sensor, then resolving power of the whole has an asymptotic relationship with the resolution of the sensor.

Thank-you.  I think you've nicely answered my question from the first page of this thread.

Still... there's something about the explanation that seems to be missing for me...  Is there a contrast limit or something in place when making these calculations?
Otherwise it only seems logical that a lens capable of resolving 150 lp/mm (at some contrast ratio) should be able to resolve 100 lp/mm (eg. ~d800e) which is roughly the max resolving power of a sensor, even if it's at some reduced contrast ratio.  :-\

67
Third Party Manufacturers / Re: Anyone own both Canon and Nikon
« on: July 07, 2014, 09:26:49 PM »
Usually this query garners fervent rhetoric from those faithfully wedded to Canon. :)

I actually divorced my 5d2 and hooked up with some D800s and plenty of other Nikon gear specifically for landscape purposes, tho not the 24-70mm.

I had a very early production 5d2 and it was very noisy, complete with perceptible vertical banding in midtones like clear blue sky and it got worse as you went into the shadows.  Metering was randomly off, but it behaved consistently in full manual.  That camera was certainly not up to spec for serious landscape work and was a very disappointing experience for me after all the positive ones I had with my earlier Canon bodies.

Nikons with Sony sensors eliminated banding noise problems completely from my workflow, what a pleasure!

As some state, the DR difference between canon and d8x0 is not that big a deal, and for the most part that's true, altho I'll take all the DR I can get.

What's related to DR, however, but not yet mentioned in this thread, is the Fixed Pattern Noise issues (vertical stripes) that Canon is only recently making incremental improvements on.  The 5d3 is not significantly better than the 5d2 in this regard.  The 70D is probably the best crop body from Canon in this regard but still no match for the cleaner files you'll get from any Sony Exmor equipped body (nikon, pentax, Fuji?)
Now I likely had a lemon of a 5d2 but the early production 5d3 I tested still wasn't much better.  If you need the best low ISO performance, get an ABC camera (anybody but canon).

Summary; if you currently shoot Canon for landscape, and you are satisfied with the results, then a D810 is not likely to impress you all that much more.  If you need to heavily process your raw files, the D8x0 will provide considerably more leeway to do so, especially in the shadows.  The extra MP of the D800 may be useful if you're printing larger than 36" wide but you do need good glass and technique to get the best results from it.

As for Nikon's 14-24mm lens, I use it.  It's very nice, but it's far from perfect.  It's fun to use, provides fantastic ultrawide images but can have significant CA in the corners.  But, so far there's really nothing else like it.

An effective alternative is Samyang's 14mm prime + Canon's new 16-35 f/4L combo.

Edit: condition altered on leading statement.

68
Lenses / Re: Canon EF 50mm f/1.8 (1st gen., metal mount)
« on: July 05, 2014, 07:53:05 PM »
Can't go wrong for the price you're paying for it. ;)

Indeed. And if its in good working order, I wonder if I should sell off my 50mm f/1.4 to start saving up for some other things I need. I'm not dying to part with it, but that would just add to the value of this gift.

If you can, spend some time comparing the 2 lenses.  I wouldn't be too quick to dispose of the /1.4 version, it's a decent lens and actually has a bit of personality at times.  I can't count how many different 50mm lenses I have, they're all a little different, but very similar.

69
PowerShot Cameras / Re: G1x vs. G16 vs. ??
« on: July 04, 2014, 01:01:41 AM »
if you have roomy pockets, Fuji XE1 + 27mm pancake prime is not very big
Same lens fits on the much smaller XM1 and XA1 which also come kitted with a very good but slow 16-50 zoom.
APSC sensor and very good IQ altho dim, low contrast subjects can be hard to AF.
OTOH, the Fuji X-20 has is also worth a look.

70
Lenses / Re: 70-200 f2.8ii or i
« on: July 03, 2014, 01:04:35 AM »
..Neither have direct equals in other bands which says a lot about the quality of these lenses.


uhmmm..  the Nikon 70-200 f/4 VR may not be pro quality build but it's optically quite a good performer and is, for example, one of the better lenses to use on a D800e for maximum resolution.

So there's one.

And the Tamron 70-200 f/2.8 VC is no slouch either, turning in a similarly good performance.
That's 2 other options or at least one if you want an EF mount.

71
Lenses / Re: Canon EF 50mm f/1.8 (1st gen., metal mount)
« on: July 03, 2014, 12:59:50 AM »
the older one doesn't just have a metal mount, it has a distance scale that's part-way useful.
it has a longer focus throw so it's also easier to focus manually than the v2, but it can also be slower to AF than the short-throw v2
The focus feature alone may make it more useful for some budget video work.
I have both versions, I think they're about the same optically, never compared them for that purpose.  I prefer the handling of the v1, even if it's a tad slower to AF at times.  v2 is definitely better for grabbing some candid shots as it's quicker to AF.
Can't go wrong for the price you're paying for it. ;)

72
I shoot very little landscape.  Virtually everything I shoot is alive, and occasionally I jumping around doing gymnastics or trampoline indoors in horrible light.  It is a struggle to get a fast enough shutter speed without going 1-2 stops above 3200.  Then I am limited to how much I can blow it up, because the image really has little detail.

Sounds like you're gonna need a decent full-frame body with a very good AF system to get what you want, and a fast lens to go with it, both in terms of light gathering and AF speed.
It aint gonna be cheap.

73
Third Party Manufacturers / Re: D810!!!
« on: July 02, 2014, 12:54:05 AM »
Stupid many of you thinking about buttons and stuff, if you buy a new beautiful car you don´t think about the buttons YOU GET USED TO IT ... i´ve been a canon owner since 2008 when i started shooting , and been shooting aurora, volcano's and models and using 1ds mk III now , i like it but i´ve been waiting for something like the d810.
Really cant wait for the results in aurora and night shooting and the d810 really F****d the 5d mk III up in video shooting BIG differences so grow up and think about the facts if you really are a good shooter and need a better quality in your photos, if not stick to your favorite. As in now Nikon got the best one on the market ( sorry to say for you religious people )  but it´s a fact

all the best to you
Gunnar

Poor ergonomics can spoil one's experience. (I'm not saying Canon has better ergonomics, I've never used Nikon cameras so can't compare). But I encounter poorly designed products every day, and it's depressing. Somebody actually designed a jug or kettle that spills when you pour, or tissue that tears anywhere but the perforations, or plastic film that requires a set of surgical tools to remove. Sure, we can (and usually have to) get used to these things, but I don't think it's asking too much that these problems are ironed out before going into production.

Of course, these are much more clear cut than button positions on a camera, I suspect, which is more a matter of personal taste. Fwiw I also have my dials programmed so one does ISO with a button pushed down - it is a lot quicker than the other cameras I've used, and tiny differences can add up to a better experience.

Canon's ergonomics and intuitive controls are still my favorites, despite how some buttons layouts tend to drift around from body to body.

The most vexatious ergnomics has to be on my Fuji XT1; very enjoyable camera to use except my early production model has THE WORST buttons ever put on top level body I've ever experienced.  I darn near need an ice-pick to operate the L cursor button.  I thought the 60D had some mushy-flush buttons but the XT1 takes the big raspberry in that regard.

So yes, poor ergonomics or funky control operations can certainly make a potentially good imaging tool not live up to its potential.
I presume the D810 buttons and controls are pretty similar to the D800's and they're decent, not fantastic.  One can learn to live with them and customize a few to improve the overall experience and yes, even shoot fairly adeptly with one hand, if necessary.

74
Lenses / Re: 70-200 f2.8ii or i
« on: July 02, 2014, 12:28:39 AM »
Regarding IQ, the 70-200 f/2.8L II IS is best, the 70-200 f/4L IS is 2nd best, and then the 70-200 f/2.8L I lens.  It is a very good lens.

I had the non-IS, OK
had the IS v1, OK at the short end and very soft at the long end.*
sold it, got the v2, very nice and sharp, some CA in FF corners.
Found v2 could render some absolutely hideous bokeh at times, too often for my liking, so sold it too.  Busy backgrounds that were near the transition zone could look aweful, not like the smoother rendering of other lenses.  That can be the price you pay for a well-corrected lens.

I prefer the overall image balance I get from am older Tamron, pre VC model.  The newest Tamron is pretty decent for the $ if you don't need the toughness or caché of the big white piece of pipe.  What you save there allows you to buy their 24-70/2.8 VC also.
It really depends on what you need the lens to do.  There's more to consider than just sharpness or how effective the stabilization is or how much CA there is.

* Turned out my v1 was not so much soft at the long end as front focusing quite badly at greater subject distances.  Discovered that when MF'd images at 200mm were considerably sharper than AF shots.

75
Canon General / Re: Gear Sale/Separation Anxiety?
« on: June 29, 2014, 02:05:17 PM »
No regrets after selling anything. It may have happened at the very first time but later when I defined what I needed and what to look for, no regrets at all.
Specially, most photographers consider a 50mm a must lens to have, I have bought and sold four and no regrets, including the 50L.

I DO regret selling my well-worn old 50/1.4 USM and keeping the new one in a box which turned out to be incapable of focusing properly.  I really shoulda checked it out before making that decision, not well AFTER the warranty expired.  :-[

Pages: 1 ... 3 4 [5] 6 7 ... 64