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| Moderated by: chrisbet, | Topic closed | |
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jk
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I am sure it must be possible to build an SD card to XQD slot alternative so we can use our XQD card slot cameras with regular SD cards. SD card pinout. Attachment: 9192FBC1-1D19-419F-91E2-2C5473801754.png (Downloaded 33 times) |
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jk
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XQD card pinout. XQD card is a memory card format primarily developed for flash memory cards. It uses PCI Express as a data transfer interface. At 7 September 2016, the CFA announced the successor of XQD, CFexpress. This new standard uses the same form-factor and interface but uses the NVMe protocol for higher speeds, lower latencies and lower power consumption. This url has a lot of information. http://pinouts.ru/Slots/pci_express_pinout.shtml PCI-E is a serial bus which uses two low-voltage differential LVDS pairs, at 2.5Gb/s in each direction [one transmit, and one receive pair]. PCI Express supports 1x [2.5Gbps], 2x, 4x, 8x, 12x, 16x, and 32x bus widths [transmit / receive pairs]. The differential pins [Lanes] listed in the pin out table above are LVDS which stands for: Low Voltage Differential Signaling. PCI-Express 1x Connector Pin-Out Pin Side B Connector Side A Connector # Name Description Name Description 1 +12v +12 volt power PRSNT#1 Hot plug presence detect 2 +12v +12 volt power +12v +12 volt power 3 +12v +12 volt power +12v +12 volt power 4 GND Ground GND Ground 5 SMCLK SMBus clock JTAG2 TCK 6 SMDAT SMBus data JTAG3 TDI 7 GND Ground JTAG4 TDO 8 +3.3v +3.3 volt power JTAG5 TMS 9 JTAG1 +TRST# +3.3v +3.3 volt power 10 3.3Vaux 3.3v volt power +3.3v +3.3 volt power 11 WAKE# Link Reactivation PWRGD Power Good Mechanical Key 12 RSVD Reserved GND Ground 13 GND Ground REFCLK+ Reference Clock Differential pair 14 HSOp(0) Transmitter Lane 0, Differential pair REFCLK- 15 HSOn(0) GND Ground 16 GND Ground HSIp(0) Receiver Lane 0, Differential pair 17 PRSNT#2 Hotplug detect HSIn(0) 18 GND Ground GND Ground Attachment: 64EEDC30-3FF9-41A2-93FE-D6A99E89F022.jpeg (Downloaded 21 times) |
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jk
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My electronics knowledge is not good enough to know how difficult it is to build an adapter interface to allow SD cards in an XQD slot. I am sure it must be possible. |
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jk
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Looking at this I wonder if this is the beast. https://www.ebay.co.uk/itm/SD-SDHC-TF-MMC-Memory-Card-to-laptop-Mini-PCI-e-reader-adapter-as-SSD/253228525382?hash=item3af598a746:g:TRwAAOSwUwFZ8rDU I will need to compare the pinouts of an XQD card and this card. |
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jk
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I am sure it must be possible to build an SD card to XQD slot alternative so we can use our XQD card slot cameras with regular SD cards. |
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Robert
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Reposted from Mirrorless camera thread. My understanding is SD and XQD are fundamentally different types of data transmission protocols. I don't believe that are simply the same thing with different physical interfaces. From what I can gather the XQD cards use a variation of PCIe, where SD cards use a variation of SATA and CF cards are an implementation of ATA (IDE) protocols. PCIe data transmission is very much faster than SATA and is used to directly access the CPU with bulk data without the intervention of controllers. An example being M2 drives which can transmit data at extremely high data rates like ~2000MB/sec directly to the PCIe bus. The XQD cards may be a variation of the M2 storage in a different form, in which case they are the future. My (simplistic) understanding is the SD card system in a camera includes a controller to assemble the bit groups into an orderly, managed procession of data. The XQD communication is MUCH simpler and just dumps the raw data from the camera on the host (computer) and lets the potentially more powerful host sort things out to create the appropriate final storage device protocol. An 'adaptor' would not just be physical, it would need powerful and sophisticated circuitry to control and order the data output to the SD card. This task is normally carried out by an SD card equipped camera. The underlying reliability and speed of the XQD card would seem to me to rely on relieving the camera from detailed data control tasks, which speeds things up, saves power and is more efficient, tasking the receiving host (computer) to order, control and assemble the data for storage. A task which it's obviously much better equipped, having powerful processors and controllers. It seems this is how the XQD card saves time and can absorb data much quicker because less processing takes place at this stage because it's at PCIe bus level, direct processor, unrefined data. http://www.dvxuser.com/V6/archive/index.php/t-328503.html 'AtticusLake' seems to know what he (she?) is talking about. |
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Robert
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jk wrote:Looking at this I wonder if this is the beast. That appears to be an adaptor from the M2 PCIe interface to allow an SD card to act as the data storage medium. There are different M2 keys, I am not yet clear what the differences are, I suspect they are voltage related. To be honest I haven't absorbed the content of this thread yet since I have just researched and written up the above post for the previous entry in the mirrorless thread. |
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jk
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Thanks Robert that is a really useful post. Always good to find out new technology stuff. |
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Robert
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While I can see and sympathise with your aims, an indignant response to being forced to adopt a storage medium which is far better than you feel you need, I really don't see the proposal working in practice. It isn't just about speed, an XQD camera has been relieved of the hardware and firmware which ordered the data into a form the SD (or CF) card could store. This speeds up the storage process and saves energy, reduces battery consumption. The move to PCIe storage is becoming universal, speed and reduced energy consumption are the result. How often do you use a spinning CF card? LOL Economy of scale will eventually come into play once everybody adopts the new medium. I am now running my Mac Pro on PCIe cards with directly mounted SSDs and the difference is amazing. Eventually I will move onto an M2 for the OS. I have tried one but it's been flashed for PC format and refused to be flashed back to Mac. I am seeing speeds of well over 1000MB/sec, even my external striped RAID G-drive was passing 400+MB/sec yesterday. PCIe SSD booting from chime to signing in is a mere 23 seconds. SATA SSD booting was over a minute. With spinning drive it was ... go have a cuppa! LOL |
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jk
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Just finished reading the link you posted and been considering the technical reading around. XQD it is! I just need to accept the change as being a longer term improvement. Same thing happened with CF to SD. Just do it. If you can afford the camera then you need to afford the media. I already have D850, D500 that use XQD so Z7 is just one more. |
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Robert
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You can't really take the new cameras in isolation, while they will take the old lenses, and push them to the limits and beyond, for that many of us can be thankful! However the cards are an integral part of the camera system in this case. Not having experienced 14bit 45megapixel images I can only imagine the stress that imposes on the computer. I suspect anyone producing large volumes of these images must need prodigious storage capacity and very powerful processors. Unless anyone really needs the ultra high resolution I would have thought the Z6 would satisfy most photographers needs. |
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Eric
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Robert wrote:I suspect anyone producing large volumes of these images must need prodigious storage capacity and very powerful processors. Or a machine gun, if they think firing relentlessly is the answer.
That's my feeling...and probably choice 24mp on a full frame has long been the perceived sweet spot. It will be interesting to see if that still holds true with the Zbods. My concern with the 45mp on a lightweight body is the risk of sloppy technique, ruining the benefit of the extra mp. |
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jk
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Eric wrote: Robert wrote: My concern with the 45mp on a lightweight body is the risk of sloppy technique, ruining the benefit of the extra mp. Yes I certainly agree with both of you wrt to machine gunning. My D850 is used selectively and only where I really want/need this extra resolution. I am using it currently as all my other gear is in UK and I just have my alternative lenses and the D850 and 24-120 with me here in Spain. The 24MP from my D600 if framed correctly gives great results, but the D800 and D850 dive comfort for cropping! |
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Eric
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jk wrote:Eric wrote:Robert wrote: The debate has always been, whether high density pixel sensors are suitable for day to day photography as opposed to special event work, because of the greater precision in technique to maximise their potential quality. I have long thought a 24mp full frame is ideal for general photography. The D750 fulfilled this role admirably for me for some time. To be honest I am kicking myself I got rid of it to 'concentrate' on Fuji. But that's another story. |
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Robert
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In a sense you already have a high density sensor in the D500, if the motivation for FX high density sensor to allow maximum cropping then why bother with a large sensor and throw the image periphery away, is the question I ask myself. I think the Z6 looses out very slightly in ISO and dynamic range but otherwise it's as good as the Z7. I'm surprised there is no word of a provincial Roadshow series, like when they launched the D5 - D500. The D3 sensor could do with another good clean up! LOL |
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Eric
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Robert wrote:In a sense you already have a high density sensor in the D500, if the motivation for FX high density sensor to allow maximum cropping then why bother with a large sensor and throw the image periphery away, is the question I ask myself. Yes I realise the D500 itself is high density and that's exactly why I want a lesser density sensor on a walk around camera. I could quite happily dedicate the D500 solely to wildlife and sports where, dare I say it, I would be more precise in my technique.  But as you know with the D3, a full frame camera is so much 'nicer' to use. So I may well have a look at the Z6 to fulfil both that requirement and the lighter weight. But if it doesn't pass muster, I may go back to a D750 or a D610 for general stuff.  |
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jk
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Two caveats. 1. Yes the D500 is a DX sensor but only 21MP. 2. I dont think that a mirrorless camera will match the AF speed of a DSLR with current technology. I think that you need to get the Z6 or Z7 and test for general use then decide if it works for birding. If you want to meet up sometime after if get my Z7 then you are welcome to test on the day as I will use D850 or XT2. |
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Eric
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jk wrote:Two caveats. I would probably be happy to just have a Z6 for general use and keep the D500 for birding/sport etc for now. I would be surprised if the cropability and functionality of even the Z7 matched the D850. But will wait to see. There are loose plans for us birding forum members to meet up in early October on NNorfolk Coast ....you are more than welcome to join us...as are ANY members. It could turn into a camera/lens evaluation day ....which would clear all the twitchers out of the hide.  |
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Robert
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Even with my recent offering I don't think I qualify as a bird photographer but I have it pencilled in on my calendar.  |
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Eric
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Robert wrote:Even with my recent offering I don't think I qualify as a bird photographer but I have it pencilled in on my calendar. Once you've sat for a few hours in a windy NNorffolk hide on a cold October day...you will |
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Robert
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Eric wrote:Once you've sat for a few hours in a windy NNorffolk hide on a cold October day...you will Yes, I get what you mean! Perhaps we can drive the cars right up to the sea wall this time? I have gas stove, cuppas all round! |
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amazing50
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Found the XQD info interesting. Looks like I'll have to shell out about $300CDN for a card. Now I'll have to find a new spot to store my chewing gum. |
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jk
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If I can get away from Cornwall then I would be up for the trip but October may be a bit early. The Z7 wont arrive until end of September and the Z6 will be sometime in November. I think that Spring time may be a better option for me. |
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jk
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Back on Topic. The UHS-II bus on SD cards goes up to 312 MB/s transfer speed maximum, which is not as fast as the new G series XQD cards. XQD can theoretically handle 1000 MB/s, which gives it a lot of room for growth. That's down to XQD using a different bus (PCI Express), which makes it physically incompatible. I think at this point we can close this discussion of an adapter for SD cards in an XQD slot as being not feasible! I will lock this thread at this point. |
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| A small amount of member data is captured and held in an attempt to reduce spammers and to manage users. This site also uses cookies to ensure ease of use. In order to comply with new DPR regulations you are required to agree/disagree with this process. If you do not agree then please email the Admins using info@nikondsl.uk Thank you. |