BJL

Lives in United States United States
Joined on Dec 17, 2002

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Total: 279, showing: 21 – 40
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In reply to:

Irakly Shanidze: What a lovely review... Yet what it is really missing is an understanding why we need medium format in the first place. So, listen up :)

It is all about lenses. More precisely, about a fundamental conflict between sharpness and micro-contrast. The conflict stems from the fact that the smaller the frame is, the higher are requirements for lens resolution. More resolution means more edge sharpness, means higher overall contrast. That, in turn, prevent from increasing micro-contrast. Larger frame means less need for high resolution, which, in turn, makes it easier to design a lens with higher micro-contrast.

Now, what is micro-contrast, and why do we want it? It is the micro-contrast that makes pictures look alive. Lenses with high sharpness and low micro-contrast (like Sigma Art series, for instance) render a highly detailed image that looks flat. A high micro-contrast lens creates an image that looks three-dimensional even when it is not critically sharp.

@Preternatural Stuff: actually, the article points out that in this case (and often with medium format vs 35mm format) the larger format does not give much in the way of options for less DOF, because the lenses for a format larger than 35mm tend to have higher minimum f-stops, (particularly in leaf-shutter systems like Hasselblad's.) This roughly cancels out the DOF difference in minimum DOF, which only applies if you assume equal f-stop in the different formats—or even puts 35mm ahead in that "contest".

Not that any MF or larger format user I know care much about striving for extremes of shallow DOF: they are instead mostly stopping down to get enough DOF, with "wide open" used only for composing, for accurate focusing and a bright image in the OVF.

More resolution, finer tonal gradations, and less lens abberations (related to typically using higher f-stops) are far more often the arguments I hear for using MF over 35mm.

Link | Posted on Mar 27, 2017 at 15:49 UTC
In reply to:

Irakly Shanidze: What a lovely review... Yet what it is really missing is an understanding why we need medium format in the first place. So, listen up :)

It is all about lenses. More precisely, about a fundamental conflict between sharpness and micro-contrast. The conflict stems from the fact that the smaller the frame is, the higher are requirements for lens resolution. More resolution means more edge sharpness, means higher overall contrast. That, in turn, prevent from increasing micro-contrast. Larger frame means less need for high resolution, which, in turn, makes it easier to design a lens with higher micro-contrast.

Now, what is micro-contrast, and why do we want it? It is the micro-contrast that makes pictures look alive. Lenses with high sharpness and low micro-contrast (like Sigma Art series, for instance) render a highly detailed image that looks flat. A high micro-contrast lens creates an image that looks three-dimensional even when it is not critically sharp.

About micro-contrast: my read is that this is the familiar fact that with a smaller format, the lenses of proportionately smaller focal length used to get the same Field Of View need proportionally higher resolution (in lines per mm); more carefully, a target like 50% MTF needs to be achieved at proportionately higher lpmm. What I have seen from the best lenses for formats from Four Thirds to 35mm to 44x33mm and up is that they often do have MTF performance that increases as the format size gets smaller; for example Four Thirds and MFT lens MTF graphs are given for 60 and 20 lpmm vs the common 30 and 10 lpmm for 35mm format. Optics tends to allow this: scaling down a lens design to the smaller focal length and image circle needed to get the same FOV coverage on a smaller sensor tends to maintain roughly the same angular resolution and so scales up the resolution—BUT the manufacturing tolerances needed to get the results that the design promises can become more challenging.

Link | Posted on Mar 27, 2017 at 15:36 UTC
In reply to:

Pan50: All well and good but you use a medium format camera for landscape shots and commercial work where Resolution is important and shallow DoF is not so relevant. If you're shooting at f5.6 and higher, then medium format captures more light than FF.
I wish Fuji had gone into the FF market but they do such a great job at APS-C that I can see why they skipped over it.

Arastoo (sorry for the typo), I agree with most of what you say. A lot of "equivalent aperture" arguments in favor of larger formats ignore that bit about needing to increase the exposure index ("ISO speed") to get the same DOF _and_the_same_shutter_speed_.
That is why I see a core advantage of formats larger than 36x24mmm being when used at base ISO speed, and therefore requiring _longer_exposure_times_ when seeking the same DOF. When a larger sensor is exposed like this, and so gets close to full well capacity in highlights, it has a good change of gathering more total photons, helping DR, SNR and/or detail. For example, the larger sensor could have:
(1) more pixels of the same size as a smaller sensor, so getting about the same photon count on average as the smaller sensor, giving more detail and similar DR and SNR, or
(2) an equal number of larger pixels, each getting more light, giving more DR, better SNR, about equal detail.

All assuming well capacity per unit area is similar!

Link | Posted on Mar 25, 2017 at 20:55 UTC
In reply to:

Pan50: All well and good but you use a medium format camera for landscape shots and commercial work where Resolution is important and shallow DoF is not so relevant. If you're shooting at f5.6 and higher, then medium format captures more light than FF.
I wish Fuji had gone into the FF market but they do such a great job at APS-C that I can see why they skipped over it.

@Aristo: the point is that more total light can be gathered, typically by longer exposure times at base ISO speed. Actually the higher f-stop needed to get the same DOF in a larger format means less intense illumination and equal total light gathering rate across the whole sensor, so longer exposure times are often essential to getting the main IQ advantage of a larger format.

Link | Posted on Mar 24, 2017 at 11:29 UTC
In reply to:

Irakly Shanidze: What a lovely review... Yet what it is really missing is an understanding why we need medium format in the first place. So, listen up :)

It is all about lenses. More precisely, about a fundamental conflict between sharpness and micro-contrast. The conflict stems from the fact that the smaller the frame is, the higher are requirements for lens resolution. More resolution means more edge sharpness, means higher overall contrast. That, in turn, prevent from increasing micro-contrast. Larger frame means less need for high resolution, which, in turn, makes it easier to design a lens with higher micro-contrast.

Now, what is micro-contrast, and why do we want it? It is the micro-contrast that makes pictures look alive. Lenses with high sharpness and low micro-contrast (like Sigma Art series, for instance) render a highly detailed image that looks flat. A high micro-contrast lens creates an image that looks three-dimensional even when it is not critically sharp.

Can you point me to a definition of micro-contrast and an explanation of why scaling down for a smaller format to a shorter focal length of higher resolution (in lines per mm; same in lines per picture height) reduces micro-contrast and how that makes an image "more flat, less 3D"?

I do expect that lens optics will ultimately be a natural advantage of larger formats, but I want the details!

Link | Posted on Mar 24, 2017 at 11:23 UTC

A good article overall; my only complaint is that no current 36x24mm format camera matches both the DR and resolution of these 44x33mm format cameras. For now, the performance gap been 36x24 and 44x33 is small, but any 36x24 options does sacrifice a bit in either resolution (Nikon, Sony, Pentax) or DR (Canon).

As far as I can tell, the traditional advantages of larger formats—before the digital photography forum obsession with SNR, high ISO and "BOKEH"—have been related mostly to DR (related to handling of fine tonal gradations and scenes of high subject brightness range), detail (pixel counts and lens resolution in "lines per picture height"), along with advantages in lens performance, partly from lower aberrations and such, due to working at higher f-stops (as is the case when seeking a given DOF). As in "base-ISO and never mind the shutter speed: use a tripod or flash when IS is not enough."

Link | Posted on Mar 24, 2017 at 02:45 UTC as 102nd comment
In reply to:

princecody: Does Fuji make their own chips?

This article suggests that there might be more customization than I thought, including deeper wells for more highlight tolerance (and so 1/3 stop lower base ISO speed)—though the language is rather garbled.

http://fujifilm-x.com/de/x-stories/gfx-technologies-1/

Link | Posted on Mar 3, 2017 at 00:01 UTC
In reply to:

Arnold Attard: Fuji's GFX quasi medium format is strategically competing with Full Frame. The sensor size is not a full blown 6x6 medium format but larger than 24x36. They have achieved a substantial technical and production head start on Sony, Canon and Nikon.
For street photographers full frame no longer makes any sense and the APS-C is here to stay. With a 33x44 sensor Fujifilm virtually almost doubles the sensor's optical performance of a 24x36. Prices will inevitably align in the not too distant future to current high end full frame cameras. This is called strategic marketing! Being an X-pro2 user I'd love to see a GFX X-pro22.

With digital, the old 6x6 (56x56mm) film format is a rather irrelevant comparison. Current medium format systems are all based on 56x42mm ("645") format for film backs, and the biggest sensors are slightly smaller at 54x40mm.

I like Fujifilm's choice of formats: 24x16 and 44x33. With EVF camera systems and their all-new lens systems, I see no reason to conform to the formats of film, laid down almost a century ago, and the size ratio between these two is a bit more than between the 36x24 to 56x42 film formats.

Link | Posted on Mar 1, 2017 at 22:34 UTC
In reply to:

princecody: Does Fuji make their own chips?

HB1969, thanks for the extra details. Let me rephrase then that the whole sensor is manufactured by Sony, and the electronic part is also designed by Sony, but with custom toppings (CFAs and micro lenses) designed by FujiFilm.

P. S. While we are debating the fine points: the company is FujiFILM, as it clearly says on the front of their cameras. Many Japanese companies have "Fuji" as part of their name, and for example while you might think that "Fuji America" is the US distributer for this camera, in fact here is the company that puts the name "Fuji" on its products: http://www.fujiamerica.com/evolution.html

Link | Posted on Mar 1, 2017 at 21:46 UTC
In reply to:

princecody: Does Fuji make their own chips?

FujiFilm uses Sony CMOS sensors these days: the GFX uses the same 44x33mm Sony sensor as several other cameras from Hasselblad, Pentax and Phase One.
Sometimes Fujifilm uses its own custom Color Filter Arrays on those sensors ("X-Trans"), but the electronic part is still from Sony.

FujiFilm did develop some of its own CCD sensors, called "SuperCCD", but has not developed its own CMOS sensors.

Link | Posted on Feb 24, 2017 at 14:53 UTC
On article Photokina 2016: Hands-on with Hasselblad X1D (147 comments in total)
In reply to:

Louschro: The XCD 30mm F3.5 offers the same FOV and the same max aperture diameter like the Panasonic 12mm F1,4. If looking only at the low light performance there is no advantage for the Hasselblad because of the same light gathering.

"shallower DOF": true if the larger format uses the same aperture ratio (and this a larger aperture diameter), but in that comparison of 30mm/3.5 with the 44x33mm sensor to 12mm/1.4 with a 4/3" [17.3x13mm] sensor, the f-stop difference is just right to cancels that out: those two lens will give the same DOF when each is used wide-open.

But never mind: I have never read an experienced medium format user talk about extremely shallow DOF as an important reason for using that format, and MF lens usually have high minimum f-stops than ones for 35mm format, for example. Instead, higher resolution, finer tonal gradations (more dynamic range) and lens quality seem more important motivations of medium format users.

Link | Posted on Sep 26, 2016 at 21:37 UTC
In reply to:

Sean65: I suspect this might be offered with the M1 ii body when released. Nice and compact for a 24-200mm f4

Equivalence folks: yes, in 35mm (36x24mm) format, one could get roughly equivalent FOV and DOF from a 24-200mm, f/8 – but that lens would then need to be used at four times the ISO speed that this one can be used at to get the same shutter speed in the same lighting conditions. Some folks love to ignore the "ISO speed penalty" part of "equivalent lenses".

Link | Posted on Sep 20, 2016 at 21:19 UTC
On article Brooks Institute announces closure (132 comments in total)
In reply to:

antares103: So, a private College offers a service. An individual borrows money for said service, and the government offers this money. Then, when the individual drops out cant cut it, or enters a career field that doesn't make a whole lot of money...the college is responsible for the debt and is evil for raking in money "from the backs of taxpayers"? Yet no one holds the individual responsible for making a bad decision and/or for failing to fullfill obligations they agreed to, at their own bequest? And even more so when there are state colleges aplenty offering the same degree for considerably less?

Perhaps we as a country would learn more from making our own good decisions than from free college.

It's not a problem if one student can't make loan, but the threshold is when over 65% of students can't or don't keep up with loan payments (or when a large proportion of former students are earning to little to justify the cost of the program). A for-profit college with a default rate that high, smells like a degree mill exploiting student with unrealistic promises of career success, whip is wha a lot of for-profit clogs are these days. Though in the case of Brooks, it might just be that the earning opportunities for low-end professional photographers have been collapsing, and what they offer is no longer a good fit to the economic realities of professional photography.

For this who are skeptical of big government, the solution might be not to take out taxpayer-subsidized loans.

Link | Posted on Aug 16, 2016 at 18:49 UTC
On article Elevating X-Trans? Fujifilm X-T2 Review (2212 comments in total)
In reply to:

Kiril Karaatanasov: This battery life thing is complete fake. I took 800 shots today on my A6300 with single battery and had 41% remaining charge. I would bet I would be able to do similar with Fuji......I all depends how you use the camera. Mirrorless with full electronic shutter just use much less energy than DSLR.....I could have easily gone well beyond 1000 shots

The CIPA battery life measurement is with use of the built-in flash on half the shots. I would love to see a second measurement with no use the in-camera flash, since that is how I work almost all the time.

Link | Posted on Jul 8, 2016 at 09:41 UTC
In reply to:

marcio_napoli: Let's face it people, we play with small format because the big guns cost 40.000 bucks.

If one of those were only 6k or 7k (possible, if it were mass produced like 35mm cameras are), then ha!!! Canon / Nikon would be crushed, I mean, among enthusiasts too.

Besides action and fast AF, DMF reigns supreme on IQ.

Someone said weight? Hmm... then grow some biceps.

And this camera is really not that heavier than a FF DSLR. If you carry your D810 around, you can easily carry a Hasselblad.

Price is not the only advantage of smaller formats: they often win also on lower size and weight, better hand-holdabillty, wider lens selection, more sophisticated and flexible AF and metering, etc.

Remember that in the film era there were medium format cameras for about $2000 and less, but even then many professionals and enthusiastic amateurs chose 35mm film cameras instead – even many professionals who could have afforded an MF kit.

Some people have a good use for a two-ton truck, but I have no interest in one, even though I could afford it; a car is _better_ for my usage.

Link | Posted on Apr 10, 2016 at 01:13 UTC
In reply to:

greypixelz: haven't Panasonic gotten the message from Kai and Lok that micro4/3rds is dead? and don't they know that Pentax is the king of WR and that it had just out-sensor'ed them?

I mean, really, Panasonic! :P

@Dr_Jon and @JimW-203: yes, all I can come up with is the "DMC-L" cameras, which were Four Thirds DSLRs in the same 4/3" format as MFT. I guess Mike99999 was just confused.

Link | Posted on Mar 2, 2016 at 00:46 UTC
In reply to:

iudex: Given the current standard zooms for M4/3 this one is definitely the most interesting. The old 14-42 kit lenses are not wide enough and optically mediocre (well, a kit lens). The 12-32mm is wide, however too short. The 12-50mm is both sufficiently wide and long, but too slow. This one is wider than the kit zoom and longer than other two, so definitely the most interesting cheap zoom (well, cheap in comparison to Pro 12-40mm lens). So basically a counterpart to popular DLSR zooms like 15-85/16-85mm from N/C/P.
However I cannot get rid of a feeling that Pana could have used the advantage of smaller sensor and make a bit faster lens, e.g. a constant f4. This would fit nicely between f2,8 zooms (12-35, 12-40) and slow variable aperture kit lenses.

I would also be interested in a MFT successor to the wonderful Olympus Zuiko 12-60/2.8-60, which hopefully could be distinctly lighter than that lens, especially since I now have to use it with a mount adaptor. And it would AF better on CDAF-only bodies!

But a mid-speed lighter option like this is nice too.

P. S. Why the desire for constant f/4 zooms when a f/2.8-4 can be about the same size, weight and price? It is the maximum effective aperture size, so at the long end, that mostly dictates bulk etc.

Link | Posted on Feb 28, 2016 at 15:04 UTC
In reply to:

greypixelz: haven't Panasonic gotten the message from Kai and Lok that micro4/3rds is dead? and don't they know that Pentax is the king of WR and that it had just out-sensor'ed them?

I mean, really, Panasonic! :P

@Mike99999 Have I missed the news about Panasonic still cameras in two other larger formats, or is "L mount" an in-joke that I am missing?

Link | Posted on Feb 26, 2016 at 03:08 UTC
In reply to:

Arizona Sunset: Question - is the other travel zoom from Panasonic so bad that they needed a duplicate?

Compared to the 14-140, this is distinctly wider (12mm vs 14mm), less expensive, and with 5x zoom range vs 10x, has a good chance of being optically better. (But I await the reviews.)

As to being "more interesting at f/2.8", it would also heaver and more expensive too. There is nothing wrong with some people sometimes opting for a kit with more speed and the option of less DOF in exchange for more weight and more cost, but some of us have chosen a smaller ILC format like MFT exactly for offering a different trade-off, in the direction of a smaller and lighter kit.

Link | Posted on Feb 26, 2016 at 02:55 UTC
In reply to:

endofoto: Sony has to make difference in sensors to force us to buy new cameras. Graphene sensors can increase camera sales, bec silicon sensors cant get any better. Graphene sensors are 1000 times more light sensitive and 10 times cheaper than silicon sensors.

No: the 1000 times improvement in sensitivity was compared to previous _graphene_ sensor experiments – the number was mis-represented in the press release from the marketing division at the university where the research was done.
Silicon sensors are already detecting over half of the photons that reach them, so there is no possibility of getting more than 2 times more sensitive.

Link | Posted on Jan 30, 2016 at 21:44 UTC
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