noirdesir

noirdesir

Lives in Switzerland Switzerland
Works as a Engineer
Joined on Nov 4, 2006

Comments

Total: 208, showing: 21 – 40
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In reply to:

Almeida: What is the equivalent aperture godmanit?!

Equivalence is a very simple idea, it, eg, tells us which lens has the same AOV on the different format. But maybe nobody cares which FF lens covers a similar AOV than this lens.
Most people don't know how to calculate DOF based on optical laws (and neither do I), and what they don't understand is a priori not believed and dismissed as irrelevant.

But you don't have to understand the optical laws. It's pretty obvious that you cannot gain DOF without loosing light for a given lens and sensor size. You could call this the 'preservation of information', either you get more stuff in focus or get more light which means less noise. It only makes sense that you cannot break that relationship when changing sensor size. When there is little light, you either have a low DOF or a noisy image, there is no way out of that.

Thus, if we get the same amount of light on a different sensor size adjusting the f-stop, we also must get the same amount of DOF at that f-stop.

Direct link | Posted on Aug 5, 2014 at 19:11 UTC
In reply to:

SirSeth: Why the cost? Just curious. It seems like a good lens but I thought Ricoh was trying to bring affordable medium format to morals.

The total ILC market (mainly APS-C + FF + m43) was 17 million units last year. The total MF market was 6000 units (units meaning cameras). That is factor is factor of almost 3000 times smaller, lens development costs have to be repaid from a much, much smaller number of lens sales. Production will also less automated and optimised due to the much smaller number lenses.

http://www.forbes.com/sites/marcbabej/2013/05/08/how-leica-camera-is-reinventing-the-medium-format-market-on-its-own-terms/2/

http://www.dslrbodies.com/newsviews/cipa-numbers-still-trending.html

Direct link | Posted on Aug 5, 2014 at 13:20 UTC
In reply to:

nicolaiecostel: The aperture is not equivalent for anything, it's a fixed value. The DOF equivalence is a different thing.

People thought that if Pentax brings a cropped MF sensor to the market, in a oversized DSLR body, at 2.5-5 times cheaper than a Hassy, Phase One, they found the chicken with the golden eggs. They forgot that MF glass is MF glass expensive and all things MF come at a price.

So here you are, having just spent 5000-8500$ on a "bargain" MF Pentax, wanting to buy a modern, bespoke wide angle and realising you have to shell out 5 grand on either this zoom or that other wide angle they anounced, and that you're stuck with a cropped MF sensor that you can't remove from the camera and use in other cameras, that has 1/125 flash sync and you shoot on SD cards with limited teathering.

Why didn't they put a central shutter in the lens ? It would have been much more usefull than that OS they put in, seen the ISO and the fact that MF users shoot in controlled, stabilised environments.

The focal length is not equivalent for anything, it's a fixed value. The AOV equivalence is a different thing.

Here you go. If you want to be a smartass, I can be one too.

Direct link | Posted on Aug 5, 2014 at 13:09 UTC
On Nikon D810 Preview preview (1529 comments in total)
In reply to:

Hugo808: "in our experience it's most problematic if you're taking pictures that include fabric."

LOL, not much of a handicap for me I hate photo's of people. Bit of an own goal for a medium format camera though, fashion, weddings etc.

Technology isn't a smooth progression is it?

It ain't worse than other medium format cameras since to my knowledge they all come without an AA filter.

Direct link | Posted on Jul 30, 2014 at 20:01 UTC
In reply to:

J Jarecki: Hasselblad could have done this years ago. I sold my whole V system at firesale prices because digital had become of age. Now, after the fact, they produce a back that is outrageously priced. RIP Hasselblad.

Hasselblad actually did this years ago (five to be precise) with the release of the CFV-39 which even had a larger sensor: 36.7 x 49.0 mm (instead of only 32.9 x 43.8 mm of the CFV-50c), not to speak of all the Phase One and Leaf digital backs available for the V system.

Direct link | Posted on Jul 26, 2014 at 21:28 UTC
On Nikon D810 Preview preview (1529 comments in total)
In reply to:

Jon Holstein: I hope they decide to make a "D710", to be a mid FF model. With a nice amount of real time control, and vastly improved AF-system over the D610. If possible, a bit higher bitrate, and probably around 24MP resolution. Kinda a FF version of the D7100.

I think they can put the D610 to rest, and introduce a more entery level FF. They could skip the focus motor. Have less real-time controls. And probably lower burst-rate than the D610. Like an FF of the 5000 series. (but with two dials, instead of the single dial of the 5000 series).

And really, they should do a Df MkII. The auto-focus system really let that one down. Especially considering the low light capability of it's sensor.

The merging of 800 and 800e, plus some smaller updates, were in line of what I was expecting in a form of a D810.

Yes, but nobody yet is able to offer a FF camera for less than $1000… and it is not the cost of the AF system that is the major reason for that.

Direct link | Posted on Jun 26, 2014 at 22:25 UTC
On Nikon D810 Preview preview (1529 comments in total)
In reply to:

dave: Nikon is adding the features that are in the new Sony A7 series. Use a D lens and take it out of auto mode for recording video to manually adjust the aperture.

You don't need a 'D' lens, just a lens that is not 'G'. You don't need a lens with a distance chip, you need one with an aperture ring and that includes the plain 'AF' as well as the 'AF D' lenses, or even a MF lens.

Direct link | Posted on Jun 26, 2014 at 20:58 UTC
On Nikon D810 Preview preview (1529 comments in total)
In reply to:

Jon Holstein: I hope they decide to make a "D710", to be a mid FF model. With a nice amount of real time control, and vastly improved AF-system over the D610. If possible, a bit higher bitrate, and probably around 24MP resolution. Kinda a FF version of the D7100.

I think they can put the D610 to rest, and introduce a more entery level FF. They could skip the focus motor. Have less real-time controls. And probably lower burst-rate than the D610. Like an FF of the 5000 series. (but with two dials, instead of the single dial of the 5000 series).

And really, they should do a Df MkII. The auto-focus system really let that one down. Especially considering the low light capability of it's sensor.

The merging of 800 and 800e, plus some smaller updates, were in line of what I was expecting in a form of a D810.

There is little point in introducing another AF system between the D6x0/D7000/D5300 and the D8x0/D4 systems. Nikon doesn't need to spend money to develop a forth different DSLR PD AF system.

One can argue that nobody wants to spend $2000 and get an AF system that offers less than the 51 point coverage and thus an entry-level FF DSLR ends up in no-mans land of being too expensive for what it offers.

Direct link | Posted on Jun 26, 2014 at 20:52 UTC
On Nikon D810 Preview preview (1529 comments in total)

Higher frame rates, lower base ISO, better AF etc. are all welcome but the area were the D800 had a real deficiency is manual focus via life view due to its line-skipping sensor read out - any word on whether that has been improved?

Direct link | Posted on Jun 26, 2014 at 20:41 UTC as 247th comment | 1 reply
On Tamron SP 150-600mm F/5-6.3 Di VC USD Lab Test Review preview (217 comments in total)
In reply to:

Kevin Sutton: How can it be sharp at 600mm on FF but less sharp on APS-C?

The performance exactly in the centre will suffer from that extra 1.5x magnification. The performance in the image corners can be much better. Though usually, the fact that the DX corners sample a better performing area of the lens than the FX corners roughly evens out with the extra strain the increased magnification brings. But this can naturally vary from lens to lens, some lenses do have noticeably better corners when used on DX if the performance drop towards the corners is non-linear (ie, a sharp drop close to the FX corners). What happens between the exact centre and the DX corner will naturally be somewhere between the unavoidable performance drop in the centre and the possible improvement in the DX corners.

Direct link | Posted on Jun 26, 2014 at 02:20 UTC
On Tamron SP 150-600mm F/5-6.3 Di VC USD Lab Test Review preview (217 comments in total)
In reply to:

Kevin Sutton: How can it be sharp at 600mm on FF but less sharp on APS-C?

If a lens resolves x lp/mm, the resolution per picture height will be x * ph. And the picture height on FF is 50% larger than DX, thus, everything else equal, the resolution per picture height will be 50% larger on FF than on DX.
(All things aren't equal since the sensor resolution in pixel per millimetre will generally be higher on DX cameras which helps the resolution somewhat.)

Direct link | Posted on Jun 26, 2014 at 00:03 UTC
On Sony Alpha 7S added to test scene comparison tool article (272 comments in total)
In reply to:

km25: I my test, the 7s was the best by about 2 F stops to the Nikon D4s, the Nikon D4s was about 1.5 F stops over the Nikon Df and because I own one, A fuji X-T1. To be honest I like the Fuji X-T1 in Jpeg, better then the Df. Below ISO the Nikons and Fuji start to take over from the 7s, not in noise, but in resolution. 16MP can be considered low by some, just think were 12MP comes in. It must take fine movies. It is too bad Sony does not offer high speed lens that are native to the camera. An F/1.8 cuts near and F stop over the cameras performance.

How do they come up with different results for different cameras if they do not do any testing? Do they multiply the number of MP with the length of camera name and then take the square root?

Direct link | Posted on Jun 23, 2014 at 00:23 UTC
On Nikon D4s First Impressions Review preview (1047 comments in total)
In reply to:

Carsten Pauer 2: Is there a Reason why the fresh Nikon D4S has less DR as a 6 Years old FinePix S5 Pro ?

DxO does not attempt to rank cameras based on the performance derived from one (or three) measured properties, the only rank sensors (if we include A/D converters and things like power supply).
But they cannot stop people wanting to denigrate them (for their own satisfaction) from pretending that DxO's list of camera names shows the intention of DxO to pass of sensor rankings as camera rankings.

Let me ask you, how do you list a ranking of sensors without using the camera names? How do you ensure that others do not wilfully misrepresent you?

Direct link | Posted on Jun 23, 2014 at 00:21 UTC
On Sony Alpha 7S added to test scene comparison tool article (272 comments in total)
In reply to:

km25: I my test, the 7s was the best by about 2 F stops to the Nikon D4s, the Nikon D4s was about 1.5 F stops over the Nikon Df and because I own one, A fuji X-T1. To be honest I like the Fuji X-T1 in Jpeg, better then the Df. Below ISO the Nikons and Fuji start to take over from the 7s, not in noise, but in resolution. 16MP can be considered low by some, just think were 12MP comes in. It must take fine movies. It is too bad Sony does not offer high speed lens that are native to the camera. An F/1.8 cuts near and F stop over the cameras performance.

I have no idea what you mean with 'based on theory' apart from maybe that everything you don't understand is 'theory' for you.

Direct link | Posted on Jun 22, 2014 at 21:15 UTC
On Sony Alpha 7S added to test scene comparison tool article (272 comments in total)
In reply to:

km25: I my test, the 7s was the best by about 2 F stops to the Nikon D4s, the Nikon D4s was about 1.5 F stops over the Nikon Df and because I own one, A fuji X-T1. To be honest I like the Fuji X-T1 in Jpeg, better then the Df. Below ISO the Nikons and Fuji start to take over from the 7s, not in noise, but in resolution. 16MP can be considered low by some, just think were 12MP comes in. It must take fine movies. It is too bad Sony does not offer high speed lens that are native to the camera. An F/1.8 cuts near and F stop over the cameras performance.

Light composition can vary a lot, of course you have to select one or several standards and test the camera with them. The ideal way to test a camera would be with monochromatic light, and then one by one cover the whole visible spectrum. Once you know the response to each wavelength, you can predict exactly how it would react for any imaginable light source.

I get the impression that the only thing you would call 'real testing' is where You are presented with two images from two cameras and can decide which one You like better.

And you don't design lenses by building a prototype and tweaking it. You first do enormous amounts of simulations. And you largely don't use humans to optimise the lens design. You create an objective function and a good number of constraints and then let algorithms optimise the lens design. The human input is in selecting the objective function and the constraints.

Direct link | Posted on Jun 22, 2014 at 20:45 UTC
On Sony Alpha 7S added to test scene comparison tool article (272 comments in total)
In reply to:

km25: I my test, the 7s was the best by about 2 F stops to the Nikon D4s, the Nikon D4s was about 1.5 F stops over the Nikon Df and because I own one, A fuji X-T1. To be honest I like the Fuji X-T1 in Jpeg, better then the Df. Below ISO the Nikons and Fuji start to take over from the 7s, not in noise, but in resolution. 16MP can be considered low by some, just think were 12MP comes in. It must take fine movies. It is too bad Sony does not offer high speed lens that are native to the camera. An F/1.8 cuts near and F stop over the cameras performance.

That is the whole fricking point. You measure each component and each property separately such that you can compare each value separately. If you were to measure noise on jpegs, you would not be able to tell how much noise the sensor 'produces' and how effective the noise reduction is. Since you can combine cameras, lenses and raw converters in many different combinations, it is impossible to compare all combinations against each other, better evaluate each component separately. A better lens will be better on almost any camera and a better noise reduction will be better for most cameras.

Direct link | Posted on Jun 22, 2014 at 20:28 UTC
In reply to:

forpetessake: None of those cameras are particularly useful beyond ISO 6400, and until that point A7s is behind everybody else. Going at higher ISO it looks like A7s is cooking its raw, but it's of little use for anybody but videographers.

You cannot cook the raw to extract detail that isn't there in the first place. Otherwise you'd be able to take the A7r or 5DIII raw file and cook it yourself until you get the detail the A7s is offering.

Direct link | Posted on Jun 22, 2014 at 19:08 UTC
On Sony Alpha 7S added to test scene comparison tool article (272 comments in total)
In reply to:

km25: I my test, the 7s was the best by about 2 F stops to the Nikon D4s, the Nikon D4s was about 1.5 F stops over the Nikon Df and because I own one, A fuji X-T1. To be honest I like the Fuji X-T1 in Jpeg, better then the Df. Below ISO the Nikons and Fuji start to take over from the 7s, not in noise, but in resolution. 16MP can be considered low by some, just think were 12MP comes in. It must take fine movies. It is too bad Sony does not offer high speed lens that are native to the camera. An F/1.8 cuts near and F stop over the cameras performance.

How would you express read noise (at base ISO) by anything but a single number? And no, this is exactly what DxO is doing, they measure several parameters of sensor performance and publish the results. And for those curious enough to know what a composite score for a sensor would be they publish additionally a very crude average.

Anybody who sees this differently is just intentionally interpreting things in a way that allows them to criticise DxO. Your stance is similar to criticising a plumber for only providing plumbing jobs and not those of an electrician as well which makes him useless as a general contractor.

Direct link | Posted on Jun 22, 2014 at 18:55 UTC
On Nikon D4s First Impressions Review preview (1047 comments in total)
In reply to:

Carsten Pauer 2: Is there a Reason why the fresh Nikon D4S has less DR as a 6 Years old FinePix S5 Pro ?

That is the slanderous insinuation everybody criticising DxO is using. Somebody publishes a list of cameras sorted by their read noise and you bluster: How dare they publish a measured property. I guess you would also be opposed to somebody publishing a list of cameras sorted by their sensor resolution or by their sensor size.

Direct link | Posted on Jun 22, 2014 at 15:40 UTC
On Sony Alpha 7S added to test scene comparison tool article (272 comments in total)
In reply to:

km25: I my test, the 7s was the best by about 2 F stops to the Nikon D4s, the Nikon D4s was about 1.5 F stops over the Nikon Df and because I own one, A fuji X-T1. To be honest I like the Fuji X-T1 in Jpeg, better then the Df. Below ISO the Nikons and Fuji start to take over from the 7s, not in noise, but in resolution. 16MP can be considered low by some, just think were 12MP comes in. It must take fine movies. It is too bad Sony does not offer high speed lens that are native to the camera. An F/1.8 cuts near and F stop over the cameras performance.

Dynamic range is a useful property of a sensor to know, publishing it is not a 'failing', ditto for color depth. But apparently publishing any measured property of a sensor is heresy to you.

And you are only partially correct about the legal situation in Germany. The general rule is not that you are not allowed to drive faster than your tires are designed for but that you are required to use tires that are designed for the maximum speed of the car. The only exception is snow tires as for a long time there were no 250+ km/h snow tires (or they were very expensive) and thus you are allowed to mount snow tires with a lower limit but you are required to have a sticker on your dashboard with their speed limit (and you have to stick to it).

And I have driven cars which felt lousy at 150 km/h (their maximum) and some that felt ok at 200 km/h (on a steep incline) despite a maximum of 160 km/h on level road. Handling at 200 km/h requires different properties than handling at 80 km/h.

Direct link | Posted on Jun 22, 2014 at 15:34 UTC
Total: 208, showing: 21 – 40
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