sflxn wrote:
I see. If you read any of the m43 shutter shock threads, a lot of people speculate that the IBIS interacts with the shutter vibration and magnifies it too.
Yep, I'm familiar with IBIS shutter shock on the OM-D and this appears to be a similar phenomena.
Canon and Nikon suffers from mirror vibration. I spent years trying to figure out how to control it handheld. I just ended up adopting mirror lockup for important shots, even when handheld. Look, I knew this was going to happen. I was alone, stating my concern over lack of EFC on such a light camera weeks before anyone received theirs. All of us have THREE choices. 1, Return the camera. 2, Keep using it and hope Sony gives us the firmware to help alleviate it. 3, And lastly, we can simmer at Sony over this. It's not like those of us who will continue to use this camera aren't annoyed. We are, but what good is getting worked up over it? Lloyd and others are pressuring Sony....Show more →
I think you've forgotten the 4th option: For those of us that have yet to see any indication of vibration when used on even a 2000mm focal length telescope, just be really pleased with the A7R's performance and stop complaining!
bwana999 wrote:
I think you've forgotten the 4th option: For those of us that have yet to see any indication of vibration when used on even a 2000mm focal length telescope, just be really pleased with the A7R's performance and stop complaining!
bwa
Your forth option indicates one or multiple of these:
a) User is not able to see and understand effects of small blur. 1/4 pixel blur makes 36Mpix camera to perform equivalent or worse than 24Mpix camera. Ignorance is bliss!
b) User doesn't want or need to get maximum performance from their equipment or themselves.
c) User is not using problematic shutter speeds, which I would believe is the case with 2000mm telescope.
I haven't been following this thread closely since I'm confident Sony could simply add a configurable delay between the first and second shutter close to eliminate any trace of shock.
What I'm wondering is why Sony opted to release the A7R without the option of EFCS in the first place. Have they explained the reason why it's not available on the A7R? There must have been some problems in some odd situations when they tested the camera which made them decide to release the A7R with officially no EFCS support (even though it's just a simple FW implementation which they decided to disable). Perhaps solving those issues and enabling the EFCS option on A7R is an even better fix than the delay fix.
Rumors was that the engineers wanted to release the camera much later, but CEO move up the time table. Who knows if it had to do with EFC or lack of lens or something else.
Is also interesting to note that every sensor that has EFC and phase detect AF also has an AA filter. I read somewhere that the PDAF is implemented on the AA filter. Could the AA filter be vital to having EFC?
Yeah. Simplified, it's just a programmatic "set all pixels on sensor to black" command, and skip the physical first curtain close, instead of physically closing the first curtain to do the exact same thing. EFCS isn't a hardware implementation.
briantho wrote:
Yeah. Simplified, it's just a programmatic "set all pixels on sensor to black" command, and skip the physical first curtain close, instead of physically closing the first curtain to do the exact same thing. EFCS isn't a hardware implementation.
You know this for a fact, or are you just guessing? If it really that simple, why don't Olympus and Fuji implement it in their cameras?
In fact, for what I've read, it's not as simple as you described.
I'm no expert, but that's how it's been explained from various sources. I don't know why Oly or Fuji doesn't implement it, perhaps because of patents. What have you read that was different?
Fred Miranda wrote:
Wouldn't the camera grip + 2 batteries do the job as far as extra weight? They would add around 13oz extra weight to the camera body.
Hi Fred,
In his email Joe says, “13 ounces doesn’t work very well at all.” He and Mike ran all manner of tests varying as many parameters as they could, and settled on the 24-26 oz weight (one uses a piece of bronze, the other stainless steel). These guys are looking to use the A7R as a replacement for large medium format cameras in the field, always on tripods, and mostly with a variety of shift tilt adapters and settings. In their tests 100th of a second seems to be the place the most vibration occurs. They are trying to get Sony to add a delay setting that will eliminate the issue. Then there is the issue of which focal lengths are causing the problem, and whether it does not appear to occur when hand holding the camera. If you email me I’ll give you Joe’s email address - He and Mike and Lloyd have shared all their data. It may be worth chatting with him and posting things you feel will be of interest on your site.
I sent Joe RAW files using a short, fat, heavy Leica 180 f2.0 on a Wimberly II head, and there was no vibration visible. I also tried a Sony 70-400 I bought to use on a FS700 video camera, at 200mm, mounted on the Wimberly II head, and again there was no visible (at 100 and 200 percent) motion shake. I didn’t do the exhaustive tests they did, but when checking performance of a variety of Leica M lenses, I had the camera mounted on a tripod, and while the Leica M lens performance on the A7R wasn’t great, I didn’t see any evidence of shake. I think they have seen it primarily (or exclusively) at 85mm or longer. That said, I believe Lloyd Chambers found it at certain shutter speed ranges with the new Zeiss 55 f1.8 - you might want to check his report.
sflxn wrote:
You know this for a fact, or are you just guessing? If it really that simple, why don't Olympus and Fuji implement it in their cameras?
In fact, for what I've read, it's not as simple as you described.
Because these are rolling-shutter CMOS sensors, an EFCS involves clocking a reset on a per-row basis, the same as how the sensor is read-out on a per row basis during an exposure but much faster. Although the reset can be performed very quickly (my guess is about 500 microseconds, which equates to a shutter speed of about 1/2000), it is still done on a rolling per-row basis, which means the earliest rows reset will receive progressively more light than the later rows. This creates ghosting and GND-type exposure effects, as seen in my example here.
I'm guessing it takes a little longer to clock a reset into 36MP vs 24MP and if so, perhaps Sony thought it would compromise the IQ of too many shutter speeds for a flagship. Also, Sony's 36MP Exmor was originally designed for Nikon's D800/E, and since Nikon has never used an EFCS on a DSLR maybe Sony didn't think it was important to engineer a solution.
sflxn wrote:
Rumors was that the engineers wanted to release the camera much later, but CEO move up the time table. Who knows if it had to do with EFC or lack of lens or something else.
Not sure when Sony reports but EoY 2013 and Christmas are two good reasons to rush a product into market.
A possible way to test shutter vibration and eliminate the variables would be to take an image with shutter vibration and then compare it to an image without shutter vibration.
To take the image with NO shutter vibration have the camera set up in a dark studio, open the shutter for say 10-20seconds. While the shutter is open fire a strobe(s) off camera to expose the image. This exposure will have no vibration from a shutter release.
Then take an image normally but don't use the strobes, their duration is too short, use hot lights or similar.
If everything is the same: lens, focus, ISO, tripod mount, distance etc. the difference in the two images is shutter vibration.
ferrellmc wrote:
To take the image with NO shutter vibration have the camera set up in a dark studio, open the shutter for say 10-20seconds. While the shutter is open fire a strobe(s) off camera to expose the image. This exposure will have no vibration from a shutter release.
You wouldn't need to leave the shutter open for 10-20 seconds because in a dark room the 2ms flash would be the only light and so the exposure would be impervious to shutter vibration.
snapsy wrote:
Someone on dpreview came up with an interesting theory. Apparently Sony doesn't allow OSS to enabled on certain E-Mount lenses when used with the A7r. He theorizes this is because Sony was aware of an problem with these lenses on the A7r, either a compatibility issue and/or an issue with the A7r's shutter vibration interacting with their OSS. The proof would be whether Sony enables OSS for these same lenses on the A7. So far it's been confirmed that OSS is disabled on the 18-55mm kit lens and 55-210mm for the A7r. If anyone with an A7 has these lenses can you please try them on your A7 and see if the SteadyShot option is enabled on your camera and that it works?...Show more →
I tried using the PZ 16-50 OSS on the A7 and OSS is indeed inactive and cannot be turned on. On a side note, the combo didn't look as ridiculous as I imagined.
Wouldn't a simple solution be for Sony to enable EFCS for any exposure at 1/2000 and slower, and automatically switch to mechanical curtain at faster speed? Especially since at 1/2000 and faster SS shouldn't be noticeable anyway ...
snapsy wrote:
Because these are rolling-shutter CMOS sensors, an EFCS involves clocking a reset on a per-row basis, the same as how the sensor is read-out on a per row basis during an exposure but much faster. Although the reset can be performed very quickly (my guess is about 500 microseconds, which equates to a shutter speed of about 1/2000), it is still done on a rolling per-row basis, which means the earliest rows reset will receive progressively more light than the later rows. This creates ghosting and GND-type exposure effects, as seen in my example here.
I'm guessing it takes a little longer to clock a reset into 36MP vs 24MP and if so, perhaps Sony thought it would compromise the IQ of too many shutter speeds for a flagship. Also, Sony's 36MP Exmor was originally designed for Nikon's D800/E, and since Nikon has never used an EFCS on a DSLR maybe Sony didn't think it was important to engineer a solution. ...Show more →
