BJL

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

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Total: 389, showing: 41 – 60
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On article Panasonic officially unveils 50-200mm F2.8-4.0 ASPH (300 comments in total)
In reply to:

Edgar_in_Indy: Any word on how long it stays at f/2.8? It seems like on most zooms you lose the max aperture pretty quickly, so this would be an important piece of information before I know what to think of this lens.

The question is how quickly or slowly the minimum f-stop increases; the basic mechanics of variable minimum f-stp zooms mean that one should expect it to start that slide immediately, but so what if at 51mm, it is only up to f/2.81?

For example, I would like to how bright the lens is at 70mm, 100mm and 140mm.

Link | Posted on Feb 27, 2018 at 19:42 UTC
In reply to:

Photo_AK: No XQD, no buy.

In the long run, ProGrade Digital seems aimed at CFExpress, which looks a lot like an evolution of XQD: same form factor initially and also using PCIe, but adding more PCIe lanes for more speed and allowing more form factors later. I imagine CFExpress will add larger card sizes for extra capacity in professional video/cine cameras.

Link | Posted on Feb 24, 2018 at 15:36 UTC
In reply to:

danielw2599: Hope they advertise the write speed more clearly than they did at Lexar.

From their website https://www.progradedigital.com under DISCLOSURES:
256GB: Up to 160MB/s read speed; up to 140MB/s write speed. 16GB-128GB: Up to 160MB/s read speed; up to 150MB/s write speed.

Link | Posted on Feb 24, 2018 at 15:31 UTC
In reply to:

dr.noise: The B4 mount defines the sensor to have a diagonal size of 11 mm.

But, I hope they will also continue with Micro Cinema Camera m4/3 mount and make it more advanced & affordable as well.

I meant "suitable lenses", not "subtle lenses" Darned auto-spelling-mangler!

Link | Posted on Feb 11, 2018 at 16:21 UTC
In reply to:

Just Another Photog: I priced this out at B&H last night. To spec out the camera as shown in the promotional material would cost between $12,900 for HD only to about $45,00- if you want to shoot 4K. You see the regular HD lenses will not cover the entire, albeit small sensor. The EF lenses will, but then you loose the benefits of the eng camera, and the benefits of the lens design (constant focus when zooming).

I’m afraid BM is over stating the value of the camera by taking the RED approach of having to add so much to the body to make it work as advertised.

Shame. I was ready to order. Now it looks like Red is the best deal, or continuing to use DSLRs..

B4 lenses will cover the 11mm diagonal frame of B4 format, and as far as I can tell, the camera can produce a 4K image in its primary "4K B4 mode". I am not sure how and when the extra sensor area is used, but I am rather sure that it provides extra pixels beyond the B4 format frame, when used with lenses of larger image circles; for example when the camera is modified to use other lens mounts.

By the way, most or all zoom lenses produce an image circle that grows as they zoom in: roughly speaking, zooming in often simply magnifies the whole image circle. So even zoom lenses that are nominally for 11mm diagonal format will probably cover this larger 15mm diagonal sensor over much of their zoom range.

Link | Posted on Feb 11, 2018 at 16:20 UTC
In reply to:

dr.noise: The B4 mount defines the sensor to have a diagonal size of 11 mm.

But, I hope they will also continue with Micro Cinema Camera m4/3 mount and make it more advanced & affordable as well.

Yes, but this camera has a larger 13.056mm x 7.344mm sensor (15mm diagonal) cropping to that 11mm diagonal format "when using 4K B4 mount":
https://www.blackmagicdesign.com/products/blackmagicursabroadcast/techspecs#W-URSA-30
Maybe it can use the full sensor area with subtle lenses, like when adapted to other lens mounts.

Link | Posted on Feb 11, 2018 at 15:26 UTC
In reply to:

sh10453: Two thumbs up.
This'll give Red, Canon, Sony, Panasonic, etc., a bad headache.

@zebebito, compare to other 2/3” broadcast camera prices:
https://www.bhphotovideo.com/c/search?ci=28625&fct=fct_sensor-size_5398%7c2-3in&N=3705627353

Link | Posted on Feb 10, 2018 at 22:42 UTC
In reply to:

virtualreality: No word on sensor size?

It is mainly for B4 mount, which is based on 11mm diagonal (2/3”), but I have read that it is a bit oversized: 15mm diagonal.

Link | Posted on Feb 10, 2018 at 22:37 UTC
In reply to:

em jo photo: Sensor is 13.05mm x 7.35mm. Super-16, basically. Quite a bit smaller than m4/3, a hair smaller than 1”.

Never mind; I found the sensor size at
http://www.newsshooter.com/2018/02/02/blackmagic-design-introduces-4k-ursa-broadcast-camera/
So 15mm diagonal, compared to 11mm for 2/3” and the B4 standard and 16mm for 1”.

Link | Posted on Feb 10, 2018 at 22:33 UTC
In reply to:

em jo photo: Sensor is 13.05mm x 7.35mm. Super-16, basically. Quite a bit smaller than m4/3, a hair smaller than 1”.

Where did you get that sensor size spec? All I have found is references to the 2/3” format that goes with the B4 spec, and that is 11mm diagonal.

Link | Posted on Feb 10, 2018 at 22:17 UTC
In reply to:

BJL: About sensor size and those who want a larger sensor like 4/3" (or Super 35mm):
1) Video shutter speeds are fairly low: about twice the frame rate, so 1/60s for 30fps and so on. So the desire for high usable ISO speeds for the sake of high shutter speeds is less of an issue here than with still cameras for action photography.
2) A lot of usage is likely to be telephoto, and then (as always) doubling sensor format size doubles the focal lengths needed, so the lenses are either vastly heavier or keep weigh comparable by having about double the minimum f-stop, and so need to be operated at four times the ISO speed: not much of a gain, so long as the 2/3" sensor has enough DR.
3) Extremely shallow DOF is rarely desirable for broadcast videography, as distinct from pre-planned cinematic photography.

In fact, some good (and expensive) movies have been shot on 2/3" sensors.

@Falconeyes With video, the shutter speed is not increased in proportion to resolution; it likely stays at the same exposure time for the same frame rate. (That is what happens if the same standard shutter angle is used). So going from 2K (1080p HD) to 4K would require four times the light gathering area, not eight — and that only if you keep the same DOF in the larger format, so doubling the f-stop when going from 1/3" to 2/3". I think instead that a broadcast camera can by used with fairly low f-stop lenses and sl have enough DOF. For example, If 2/3" format can use the same f-stop as a 1/3" format phone camera, it will get substantially more light per pixel in 4K than the phone gets in 2K.

Link | Posted on Feb 10, 2018 at 17:29 UTC
In reply to:

BJL: About sensor size and those who want a larger sensor like 4/3" (or Super 35mm):
1) Video shutter speeds are fairly low: about twice the frame rate, so 1/60s for 30fps and so on. So the desire for high usable ISO speeds for the sake of high shutter speeds is less of an issue here than with still cameras for action photography.
2) A lot of usage is likely to be telephoto, and then (as always) doubling sensor format size doubles the focal lengths needed, so the lenses are either vastly heavier or keep weigh comparable by having about double the minimum f-stop, and so need to be operated at four times the ISO speed: not much of a gain, so long as the 2/3" sensor has enough DR.
3) Extremely shallow DOF is rarely desirable for broadcast videography, as distinct from pre-planned cinematic photography.

In fact, some good (and expensive) movies have been shot on 2/3" sensors.

@Ed, I agree that different shutter angles and frame rates are sometimes used for video, but this camera is aimed at broadcast work (like TV studios), where I expect that it is going to be 30fps and standard shutter angle most or all of the time. Looking at other broadcast TV cameras, the sensor size range seems to be 1/2" to 1", with even some far more expensive models than this using three 1/2" sensors. For comparison, the sensor in this one seems to be a bit bigger than 2/3", slightly smaller than 1" format.

Link | Posted on Feb 10, 2018 at 17:25 UTC

About sensor size and those who want a larger sensor like 4/3" (or Super 35mm):
1) Video shutter speeds are fairly low: about twice the frame rate, so 1/60s for 30fps and so on. So the desire for high usable ISO speeds for the sake of high shutter speeds is less of an issue here than with still cameras for action photography.
2) A lot of usage is likely to be telephoto, and then (as always) doubling sensor format size doubles the focal lengths needed, so the lenses are either vastly heavier or keep weigh comparable by having about double the minimum f-stop, and so need to be operated at four times the ISO speed: not much of a gain, so long as the 2/3" sensor has enough DR.
3) Extremely shallow DOF is rarely desirable for broadcast videography, as distinct from pre-planned cinematic photography.

In fact, some good (and expensive) movies have been shot on 2/3" sensors.

Link | Posted on Feb 10, 2018 at 00:14 UTC as 32nd comment | 4 replies
In reply to:

virtualreality: It's time to ditch the "D". Are they actually selling any non-digital cameras?
Compressed font D7500, it doesn't look good, even on DSLR with huge real-estate.

I agree: the Nikon F6 is the only Film SLR still being _sold_ new (and probably none has been _manufactured_ for years) and I have been calling them FSLRs for years now. I doubt that many people would be confused by saying just SLR for the whole category; it is as if we still called automobiles "horseless carriages".

But as this whole SLR category in now starting to slowly follow FSLRs into the sunset, it is probably too late to bother with any renaming.

Link | Posted on Jan 23, 2018 at 22:20 UTC
In reply to:

ilza: OK, so this is a “composite sensor” which reads information from 200,000,000 locations in the focal plane. What makes it it a 400MPix sensor?!

(Just for completeness: out of these 200MPix, 100% are read in G, 75% in R, and 75% in B.)

The first four measurements are at the same 100 million locations (10,000 by 10,000) and then the fifth and sixth readings are centered at different locations, straddling the previous locations, so 300 million locations in total, with 20,000 different horizontal locations and 20,000 vertical. After that, the use of 400 million output pixels is just the 20,000 X 20,000 rectangular array of output pixels needed to cover the 20,000 horizontal and 20,00 vertical positions.

Link | Posted on Jan 19, 2018 at 17:52 UTC
In reply to:

ilza: OK, so this is a “composite sensor” which reads information from 200,000,000 locations in the focal plane. What makes it it a 400MPix sensor?!

(Just for completeness: out of these 200MPix, 100% are read in G, 75% in R, and 75% in B.)

The sensor has 100 million _photosites_, and the shifting is used to make 600 million readings, used to produce 400 million _pixels_. The difference between "photosites" and "pixels" is important here, as it has been demonstrated by several previous multi-shot shifting sensor cameras that this process can give more real resolution/detail that the photosite count is capable of without multi-shot. (By the way, this success has also shown that fears of current lenses not being able to keep up with the resolution increases of new bodies are exaggerated.)

Link | Posted on Jan 18, 2018 at 17:32 UTC
In reply to:

Mike Davis: Pixel-shifting increases pixel counts without increasing the sensor dimensions. The diameter of Airy disks at the sensor plane will not shrink for any given aperture and wavelength of light, just because you started pixel shifting to quadruple the number of captured MP.

Pixel-shifting is great for increasing the resolution in the final print without increasing the print dimensions, but if you try to increase enlargement factor, you'll be increasing the size of the Airy disks in the final print, unless you open the aperture proportionately, to compensate the increase in enlargement factor.

In other words, if you're happy with the print resolution you're getting with 100 MP from this size sensor, you'll have to open up two stops to make a print that's twice as large, for the same desired print resolution and viewing distance. How does shooting at f/4.8 (instead of f/9.6) to avoid inhibiting a desired print resolution of 5 lp/mm in a 360 dpi un-resampled print sound?

Yes, 400MP wil have somewhat limited DOF once the aperture is large enough to avoid excessive diffraction. Maybe that is why it is marketed for art reproduction: photographing essentially flat subjects.

But no, format size has got nothing do with this limitation. For example, doubling sensor and pixel size would allow doubling the Airy disk diameter and so doubling the usable f-stop, but due to the doubled focal length also involved, that would gives circles of confusion at the focal plane also of twice the diameter. So if images from two formats are printed at equal image size, the prints have equal sized Airy disks and circles of confusion: same diffraction effects, same OOF effects.

Link | Posted on Jan 17, 2018 at 20:34 UTC
In reply to:

evilmagicnut: I expect those percentages are percentage of units sold. I'd be interested to know what the Canon / Sony / Olympus mirrorless breakdown is when you start talking revenue.

For mirrorless, revenue probably moves up both Sony (with its 35mm format bodies) and Panasonic (with its main strength in higher end "video first" gear). Anyway, the MFT system as a whole probably holds first place amongst mirrorless systems by either ranking.

P. S. Why does this ranking not even publish market share percentage beyond third place?

Link | Posted on Jan 17, 2018 at 20:21 UTC
In reply to:

toughluck: If Nikon has any sense, they will throw in one or two F-mount adapters for free with the camera. One for AF-S lenses only, the other for AF-S and screwdriver lenses.

I agree that there should be an adaptor, particularly for any 36x24mm format Z mount body — and I am sure there will be. But there will also be a lot of entry level customers using only Z-mount lenses, and increasing the price for them by including an unwanted adaptor with _every_ camera would be bad for sales. It might make sense to bundle the higher end 36x24mm format bodies with an adaptor

Link | Posted on Jan 16, 2018 at 18:03 UTC
In reply to:

toughluck: If Nikon has any sense, they will throw in one or two F-mount adapters for free with the camera. One for AF-S lenses only, the other for AF-S and screwdriver lenses.

There is no such thing as "free" here; just "included in the price whether you want it or not". That would be passing on part of the cost to customers who have no need for such adaptors.

Link | Posted on Jan 15, 2018 at 14:41 UTC
Total: 389, showing: 41 – 60
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