Forum Replies Created
Pete Walentin;1349 wrote:
Even it is somehow curious you do not know what kind of QC they are doing. I do not think that they have done 9k shutter releases to test if the camera is working properly. Maybe part of this is renaming of files as well.Putting on my “Retired Computer Systems Designer” hat for a moment…
There are a lot of innocuous ways this might happen. One that comes to mind is that manufacturing post-assembly tests that work at a computer “bit” level might leave the counter in a random state and later someone accidentally skipped the “reset count” step. With such small production runs building an elaborate infrastructure to prevent this is not economic compared to a simple manual checklist.
Remember that “ISO” is different in the digital world than with film. The sensitivity (“ISO”) of a digital sensor is what it is and cannot be changed; changing a digital camera's ISO setting changes the readout strategy or “the way the lab processes the roll of film”.
In both tests in David's experiment the sensor had the same state when the shutter closed since the exposure settings were the same but the readout strategy differed since the ISO setting was changed.
David's result is as I would expect: amplifying the signal in LR means that the readout noise is amplified by the same amount as the signal but changing the camera ISO setting means the camera can amplify the signal with little or no new readout noise added.
Sandisk, Panasonic and Delkin all have 64GB UHS-1 SD cards rated at ~ 95 MB/s reads. The Panasonic is rated at 45 MB/s writes, Sandisk and Delkin ~ 90 MB/s.
Just how fast any of them really are I do not know
How does this differ from the existing S 35mm f/2.5? In what circumstances would I use one instead of the other?
David Farkas;1053 wrote:
In SD, your best bet is a Class 10 SDHC card, but you'll be limited to download speeds of only about 30-40MB/s to your computer. Here, I find CF to be much, much faster.SD cards with the UHS-1 spec should be as fast as the fastest CF cards, if the camera and card reader support UHS-1. Otherwise it will only do Class 10 speeds.
You need a SD “UHS-1” USB3 card reader to get fast downloads. I don't know if there is a Firewire-800 UHS-1 capable reader yet.
I doubt the S2 can write at UHS-1 speeds. It's a hardware change to support it so it probably doesn't appear until later.
As for high capacity SD cards, I vaguely recall testing a 128 GB SDXH card once and it didn't work. I don't know if that's still true with current camera firmware. I believe this is probably just a firmware change and could be added to the S2 if Leica got enough requests.
The Markins Quickshoe has a useful safety feature:
That's a spring-loaded pin so that if you have a flat-bottom plate you can still use that shoe. But the Really Right Stuff L brackets and others have hollowed-out areas and the pin acts as a safety stop in case the shoe works a little loose…
The RRS S2 L bracket has a problem with the Markins 60mm shoe: the L bracket dovetails are small and the safety pin winds up *outside* the dovetail when the camera is in the on-axis centered spot of the quickshoe. Markins has a 48mm shoe but I'm not sure if the pin if moved close enough to the center to eliminate this issue.
How well does an Eye-fi work in an S2? Getting a radio link from it to anything else would seem to be a challenge.
Perhaps mount the S2 in a bracket and the “Access Point” radio the Eye-fi talks to on top where a flash might be? That might allow you to hold the Access Point's antenna at a particular angle to the Eye-fi so as to avoid all that metal in the S2.
There are a number of field photo storage devices such as Jobo. Can any connect to a camera directly via USB to download from the camera? I haven't tried to see if the S2 will allow USB photo downloads while shooting – it may not work.
Some Android tablets, such as Toshiba's Thrive, have a USB host port and could be connected to an S2, but you would need software that knows to copied photos from the camera.
David Farkas;472 wrote:
When I run out of space, I just open up a new card, test it and go. The used cards get transferred to the computer, and then they get piled in a neat little stack. Seriously. Extra backup.What is the problem you're addressing? This seems like a strategy to _maximize_ the likelihood of finding an SD card that fails. Thoroughly test the cards you'll use as spares and in-camera and replace them far less often.
Hard disks are so cheap now that I think that's the way to go for strong backups, but not NTFS or HFS (neither Windows nor Mac have modern filesystems). Keep an eye on http://tenscomplement.com/ for their ZFS software package for the Mac – that and external Thunderbolt or SATA disks will be by far the most reliable way to go once the tenscomplement.com product is released (but don't use USB disks).
The best reason for long-term SD storage I can think of comes from the extremely low weight-to-GB and size-to-GB ratios. A bank safety-deposit box is going to be able to back up all of a studio's library easily in SD form for off-storage to protect against fire and theft disasters.
In that picture I think the focal point was just to the right of the “8”, at about the 18 1/4 point, maybe slightly (1/32) to the right of that.
For future cameras that's something for Leica's suggestion box: provide more information at the time of shooting as to where the focus point is.
More information recorded for later inspection would be useful too. Canon records such information in files so you can see what happened after a focus disaster.
Perhaps even record the measured distance.
David Farkas;433 wrote: Just to play devil's advocate, with smaller cards and more CF card changes, you are putting more wear and tear on the connector pins, both in the camera and in the cards. I doubt with normal use you'd ever see a failure, but statistically…..
It's not just the cycle wear on the connectors but also other risks such as dropping the card, putting in the wrong card (already full), etc. My preference is to use large cards and keep swapping in the field to a bare minimum. The safest and most protected place for a card is in the camera.
I also cycle through my cards: after every shoot spare #1 goes into the camera, spare #2 goes into spare #1's slot, etc, and the card with images goes to the back of the line after being copied up to the server. The point is to not unwittingly wind up with duds as spares. I do the same cycling with batteries.
I treat all of these cards as fragile, especially SD cards, and never handle them over a hard surface.
Thunderbolt is complex and *expensive* – those $50 cables may never get cheaper if there's no way around active cables.
Unfortunately Apple is reducing support for ExpressCard. If you do have an ExpressCard slot use an eSATA card and an eSATA drive. It's well-proven technology, effective and cheap.
USB has issues besides raw bandwidth. It has had very high overhead, putting a lot of load on the system. One big advantage of eSATA is that it is as efficient as a hard disk, but that is not the case with USB at all.
I use USB 3 on my PC right now to download images (using a USB 3 card reader) Were I on my MacBook I could use a CF card to SATA adapter, SATA to eSATA cable, and eSATA ExpressCard,but that's a bit too jury-rigged for most people I think.
I don't know of any Thunderbolt solutions yet. Given the lack of early announcements cost-effective solutions may take a while.
Here's another idea: an option to enable “card readability checks”.
Every so often when the buffer is flushed and the card idle, read back the first few blocks from the most recent images written to the card. Potentially check many images in case the card has a large RAM buffer: we want to read from the flash cells.
The idea is to detect a failed card as soon as possible. I'm skeptical that a failed card will be a “silent failure” while shooting but maybe so, especially with cheap cards, and the sooner a failure is detected the better.
In future cameras that support 90 MB/s cards perhaps the camera could compute a checksum of each file as it is written and write the checksums to the card too. When the buffer/card is idle whole files and checksums could be read back and verified, all in the name of telling the photographer ASAP that something is wrong.
This is expensive in battery life to do, but a lot of people seem paranoid about card failures, and it only has to happen once to be a very expensive failure…
David Farkas;190 wrote: Okay, here is a big one I left off that I've written about before…
Dr. Zimmer, head of digital R&D, explained that noise could be reduced by either dropping the sensor readout from 24Mhz to 12Mhz or by using a dual readout vs. a quad readout from the sensor.
That's surprising: why would dual vs. quad readout make so much difference? My first thought would have been to add more readout channels and clock them slower, but he seems to imply that loses in the real world.
It might be worth asking if the hardware can do single-channel readout. If anyone has ever detected banding a single-channel readout would eliminate it. But maybe banding is already a solved problem and no longer an issue.
Either of these options would cut the continous frame rate in half and double the time from capture to review, but also would deliver a one stop improvement in noise performance.
It may not be necessary to do readout in strict row order. Perhaps they could readout every tenth row first and display the preview quickly while doing the rest of the readout to write to the card(s).
Compared to pixel binning options like Phase's Sensor+, this solution would offer full resolution not 1/4 res.
binning may increase dynamic range considerably and improve chroma resolution depending on how the sensor works.
Jeff Plomley;263 wrote: Possibly a menu item which allows the user to input an autofocus calibration offset, not unlike that offered by Nikon/Canon and others.
I don't want to have to figure out the offset and then input it to the camera: have the S2 figure it out.
Create a suitable target for focusing and post it on Leica's web site for people to print.
The printed target can be taped on a wall and the S2 aimed at it on a tripod, then a focus calibration option activated on the camera.
The camera uses normal phase detection focus to find the distance to the target.
The camera then does contrast focusing with the main sensor via a series of exposures, just like a cheap P&S. Eventually a “true distance” is calculated.
The difference between the phase detect distance and the contrast distance is saved for that lens and used whenever that lens is detected. Perhaps there could be an option to use one measured offset for all lenses without an individually measured offset (a per-camera vs.per-lens offset).
If space in the camera for firmware is tight the code can be placed on a flash card, just like a firmware update, and the routine temporarily copied into the camera and discarded at the end of calibration.
