Will the SD15 adress the shortcomings of the SD14? Will it have a larger sensor than the SD14?  Will it deliver faster image to image speed? Higher fps? Larger buffer? Will it have a better LCD? Will the SD14 have better color accuracy? Better handling of red? Will the green cast be elliminated? Will the lockup issue be gone? Will it have higher ISO? Lower noise? Is the user interface changed? Will it have LCD Live View? Video? IS? Does it still have the same dust protector, and thus the same great IR possibilities as the SD14? Will the price be like the initial or the current price of the SD14 (1600 vs. 300 USD)?.

What kind of camera is the SD15

First, it is important to realise what kind of camera the SD15 is, or rather what it NOT is. In short, it is a SD14 with improved image processing capabilities. It will have the same body as the SD14, and more important, the same sensor. The major change is the DSP. From the DP family, it has got the TRUE DSP technology. (Version II like the DP2 has.) The SD14 has no blows and whistles, neither will the SD15. Look elsewhere if you are dependent on the camera doing the job. We can expect improved IQ. More specifically, I expect better handling of red (as DP1 has) and ellimination of the green cast issue, and hopefully better noise handling.

Same sensor as in the SD14 means same resolution and crop factor (1.7x). This may be a disapointment to some, and marketing wise it is a drawback. The use of an three year old sensor will be noted (killed) by the reviewers. But it is reasonable to assume that no larger Foveon sensor was available. Until last autumn, Sigma did not control Foveon -  and Foveon might not wanted (or could not afford the development of) a FF. But those who use the SD14 today knows the capabilities of the sensor, and so do the growing number of DPx users. The TRUE processor of the DP1 gave an increment in IQ, and the TRUE-II DSP of the DP2 promises even better IQ,

Given these circumstances, I think it is a wise move of Sigma to release a SD15, instead of waiting for a FF to emerge from the lab.

A pre production DP2 shown at Focus had ISO 3200, but it has been removed in the "near-production" sample shown at PMA. I expect it to show up in a DP2 firmware upgrade, and that the same will happen for the SD15.

The LCD grows from 2,5" to 3". Hopefully this also means better LCD resolution, as the DP2 has 230.000 pixels (150.000 pixels on the SD14) but this is not known. An improved LCD is a needed improvement.

Sigma has said that the TRUE II process the image faster, but it is unknown what this means for shot to shot speed. Also the switch to SD cards is a joker, performance wise. The SD interface (with SDHD cards) + TRUE II will most certainly give an improvement to process/write time. How much improvement is unknown. No words are said about buffer size, fps or AF performance.

I also expect the SD15 to fix the lock-issue of the SD14.

Based on the pictures, the SD15 have no video or live view. IS is not likely either.

Most certainly it will use the same anti-dust system, but one could hope that the dust filter removal/inserting has been improved. However, this is not likely.

Scope of this document:

The scope of this document is to present all disclosed facts up to the release. Along with this, I will also present mine and others educated guesses, based on bits of released information and pictures..
Be warned that the design of the camera and specs may change.

Known facts: Sigma SD15

Based on released info..

	Area	Change?	SD15	SD14	Source
1	Sensor	Same	Foveon X3 with 3x4.6Mpixels	Foveon X3 with 3x4.6Mpixels	1
2	LCD size	Larger	3 inch	2,5 inch	1
4	DSP	TRUE II DSP  (developed with Fuji)	TRUE II		1
5	Card	New format	SD	CF	2
6	Processing speed	Improved			1
7	Noise	Less			2
8	Body	Basically same	A few changes (3) to User interface		3
9	Viewfinder	Same	96% (98% (hor) x 98% (ver))	96% (98% (hor) x 98% (ver))	3
10	Shutter box	Same			3
11	Quick Setting button	New			3

• The DP2's development is further advanced than the SD15 (Source: 3)
• Release date: Official date from Sigma is April 2009 (Source: 3). This is highly unlikely, as no working camera will be shown at PMA (beginning of March)

	Area		SD15	SD14	Source
1	Video mode	No. Drive Mode Wheel seems to be identical to the SD14	No	No	Picture analysis
2	Exposure modes	No new	PASM	PASM	Picture analysis
3	Live mode	No. See note *1			Picture analysis
4	Pop up flash	Same	Yes	Yes	Picture analysis
5	ISO   adjustment	New button	Separate button. (Note: *2)		Picture analysis
6	WB adjustment	Moved	Now behind the new QS button
7	AF-point selection	Button moved	Doubles with Zoom Out
8	Metering Mode adjustment	Operation changed. See Note #3	Separate button. Doubles with Zoom in	Was in the Func menu system
9	Top LCD	Yes
10	Mount	Same. See Note #4	SA	SA
11	Write indicator lamp	Position changed	Below the down arrow

• Note *1: No live mode, as Zoom in/out buttons are only for playback. (Doubles with Metering mode and AF selection points) ( Source: picture analysis)
• Note #2: (Formerly where the AF-point selection button was located). I see three possibilities on how this is operated:
1. Hold and change unidirectional (on the rear LCD) with the Command Dial. 
2. Press to scroll through (better than todays solution) on the rear LCD.
3. Press, and change unidirectional on the rear LCD with up&down. 
• Note #3: Metering mode is moved from within the Func system to a dedicated button. It may be a toggle button, probably changing between the same three Metering modes as of today (SD/14), or used with the Command Dial. This change is good. This button doubles with Zoom Out. (Source: picture analysis)
• Note #4: It remains to see if the SA mount has changed further (as from the SD10 to SD14, where it made the use of certain SA to Nikon F adaptors impossible)

The QS button.
With the release of the DP2 we have a better indication of what this button do. It seems that it is mostly a name change from the ISO/WB button, invoking 4 functions on the rear menu for control by the four way arrows. However, on the DP2 it allows access to 8 functions on the rear LCD, devided on two screens. I expect only four on the SD15. On the DP2, there are indications of how many options each function has, so it is easier to avoid pressing the arrows too many times.

Unchanged buttons & connectors: 

• PC syncro
• Flash compensation 
• DOF 
• Focus assist light
• Top LCD Illumination
• Diopter adjustment
• Drive mode wheel
• Exposure Mode wheel
• Command wheel
• Lens release button
• AEL
• Exposure compensation/Av
• OK and the four arrows
• The five buttons on the left of the LCD. (Position is moved closer to the edge to allow for a bigger LCD, and the buttons now got text printed on them, instead of beside the buttons.

Pretty certain information:

• No AA filter (as in the SD14)
• Improved colours reproductions over SD14, especially red and elliminated green cast
• ISO 50 and ISO 1600 (as in the SD14). Possibly ISO 3200.

Unknown

* LCD resolution is unknown, but let's hope it is closer to Canon 50D's 920.000 pixels than SD14's 150.000. The DP2 has 230.000 pixels on a 2,5" screen.

* Image to image speed:

Possibly better shot to shot performance, due to the TRUE II processor. It is also possible that SDHD cards will give better performance than the slow CF implementation of the SD14. My guess is a 25% improvement.

* RAW (X3F) format. As the processor is changed to TRUE-II, the RAW format may also have changed. It is surely different from the SD14 format. I guess no of the current SPP versions will support the SD15s RAW file. I expect a new SPP version with the DP2, and that this probably also will support X3Fs from the SD15.

Exif from DP2 samples indicate SPP 3.5. If this is consistant with the naming convention of previous SPP versions, it will be based on the now abandoned SPP 3 version, and we will again get Zoom and Print.

* Improved high ISO handling.

  Hopes (none of this is even hinted at)

• Larger buffer size. At least the double (or halved write time) 
• Fps higher? (I rarely need it faster, but I would not mind) 
• Shorter write time per image. Unfortunately, the switch to SD cards rules out the hope  for UDMA 4 support.
• Configurable timer for metering shutdown
• Kelvin WB
• WB fine tuning (from presets)
• Configurable options for AE/AF lock behaviour
• ISO/WB info visible in viewfinder. Configurable:
• permanent
• when adjusting
• never
• Focus calibration through menus.
• Tethered shooting.

Pure speculation

Price 1200 USD, but if the shortcomings of the SD14 is amended (faster write time, larger buffer, better high ISO, better red, no green cast), I would not be surprised if the price will be even higher than USD 1200

Delivery date:

Source	Type	Estimated delivery date	Date
Michihiro Yamaki, CEO Sigma Japan (2)	Official	April 2009	2008-09-26
Unnamed Sigma sales rep, Focus 2008 (4)	Unofficial	Spring/Summer 2009	2009-02-23
Thomas G. Sobey, Marketing Manager, Sigma US (5)	Half official	Summer 2009	2009-03-04

 

History and sources of information in this document:

Source
1	2008-09-23 – Press release Sigma announce the SD15, the successor to the SD14. Very few specs are disclosed in the Press release, but two pictures are posted, which give away some facts.Pictures of the SD15:
2	2008-09-26? – Interview with Michihiro Yamaki, CEO of Sigma Important information revealed. DSP, Card format and release date.
3	2008-09-30 – Interview with Katuzo Yamaki, Sigma. (Digicam Watch) The interview is in Japanese, but translation of key points are offered in posts in this thread at DPReview. It confirms that the SD15 mechanically will be like the SD14, with changes to the LCD and user Interface
4	2009-02-23 - Unofficial info from Focus at Imaging Photo Expo in Birmingham, UK, feb-02. http://forums.dpreview.com/forums/read.asp?forum=1027&message=31088576
5	2009-03-04 - Half-official info about delivery date, from Thomas G. Sobey, Marketing Manager, Sigma US. Reported by Amateur Photographer.