Camera Architecture

This go around, HTC put a 13 megapixel camera into the One mini 2. This in a vacuum wouldn’t be anything out of the ordinary, but in the context of the past year it’s well worth examining. After all, HTC kept the same ST VD6869 sensor across the One (M7) and One mini, and also continued to use a similar 4 megapixel camera in the form of the OV4688. Especially in light of all the rhetoric that HTC has pushed in favor of larger pixel sizes in marketing literature, it’s worth examining the camera of the One mini 2 closely.

HTC One Cameras
  HTC One mini 2 HTC One (M8)
Front Camera 5.0MP 5.0MP
Front Camera - Sensor S5K5E2
(1.12µm, 1/5")
S5K5E2
(1.12µm, 1/5")
Front Camera - Focal Length 2.79mm 1.83mm
Front Camera - Max Aperture F/2.8 F/2.0
Rear Camera - Sensor OV13850
(1.12 µm, 1/3.06")
OV4688
(2.0 µm, 1/3")
Rear Camera - Focal Length 3.82mm (28mm eff) 3.82mm (28mm eff)
Rear Camera - Max Aperture F/2.2 F/2.0
Secondary Rear Camera - Sensor - OV2722
(1.4µm, 1/5.8")

As can be seen in the table above, the same front facing camera sensor is shared by both the One mini 2 and One (M8), which is a Samsung sensor with 1.12 micron pixel size although the optical stack changes to reduce aperture size and increase focal length. The rear sensor on the One mini 2 is still an OmniVision design win, but the sensor model is the OV13850 as opposed OV4688 on the One (M8) and later production runs of the One (M7). While the sensor size is the same, as is the optics’ focal length, the differences end there as the One mini 2 has a smaller aperture at F/2.2, which is a quarter stop smaller, which means that light collection goes down as well. The lack of the second depth sensing camera also means that all of the Duocam effects such as UFocus are gone as well, which means that the One mini 2’s editing features are equivalent to the One (M7)’s.

Outside of hardware, the change in ISP is far-reaching in its effects. Zoe, Pan 360, and Dual Capture are all gone, which suggests that the ISP in the MSM8x26 series cannot support dual encode features the way that the ISP in the MSM8x74 series can. Video encoding is also severely limited as the One mini 2 only supports a maximum of 720p60 or 1080p30. This is clearly not a limitation of the camera sensor as casual examination of the OV13850’s data sheet shows that it can record data from the entire sensor at 30fps. This means that the encode blocks don’t support the necessary bandwidth for such features. It's also interesting to see that HTC has capped the maximum shutter speed in the camera to two seconds rather than four seconds in the One (M8).

In addition to these issues, the shooting experience is noticeably worse. Preview resolution and frame rate are worse than the One (M8), and it seems that autofocus speed drops as well. Shot to shot latency and burst shot capture rate both are much slower, and I suspect that this is either the product of worse random read and write speeds on the NAND or a bottleneck at the ISP. Overall then, this means that comparing the performance of the One (M8) and One mini 2 in camera will be difficult as they can be confounding factors upon camera image quality.

Introduction & Hardware Still Image Analysis: Spatial Resolution & Color Reproduction
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  • Laxaa - Monday, May 26, 2014 - link

    It baffles me that this "mini" is the same size as the M7. What does this offer that the M7 don't have on a lower price point? Reply
  • fokka - Wednesday, May 28, 2014 - link

    slightly better battery life, slightly better camera in daylight, sd slot. Reply
  • Morawka - Monday, May 26, 2014 - link

    i like last year's metal unibody much better than this. Satin aluminum feels much better in the hand, (and looks better) than this brushed aluminum look. Reply
  • krazyfrog - Monday, May 26, 2014 - link

    The brushed aluminum finish is only on the grey model. The silver and gold look like the M7. Reply
  • fokka - Wednesday, May 28, 2014 - link

    i also like the m7 design better, but not because of the brushed finish - i love brushed metal! - but the corners look better imho. it doesn't look all that rounded, more simple and also the top speaker grille is more centered. also the speaker grilles were real metal on the m7 and if you look closely at the m8 you can see that theres a rather thick clear coat on the grilles, plus not all holes are drilled all the way through. "nitpicking", yes, but on a phone that lives for its design i think those are still valid points.

    also the second (duo-) camera looks goofy and the black m7 is just absolutely gorgeous, compared to the black m8 with its appalling gold speaker grilles (sprint version).

    also (sorry for saying "also" so much!), i don't get how they get their numbers like "90% metal", or "50% metal". shure, the surface of the m8 features a couple percent more metal than the m7, but not to the extent of 90% vs. 70%. and the mini 2 sure as hell isn't down to only 50%. i'm really wondering how they calculate this to get those numbers.
    Reply
  • SetiroN - Monday, May 26, 2014 - link

    You are being WAY too kind.
    These "mini" marketing devices deserve to be bashed and put to shame. People buy them thinking they're getting a mini flagship and end up hating android.
    This is a terrible device at that price point.
    Reply
  • Laxaa - Monday, May 26, 2014 - link

    It is. The M7 is a much better buy. It might be a year old, but it's still a great smartphone. It looks better as well. Reply
  • hangfirew8 - Tuesday, May 27, 2014 - link

    Exactly what I was thinking! If they had put an 8MP camera on the M7 it would have been a better phone than this. Reply
  • fokka - Wednesday, May 28, 2014 - link

    the m7 with a larger 8mp sensor with OIS and an sd slot would have been perfect!! plus the sd801 from the m8 to seal the deal and they would have one customer more. Reply
  • r3loaded - Monday, May 26, 2014 - link

    4.5 inches is "mini" now? Reply

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