One of the new features of the iPhone 6 and 6 Plus is that it has "Focus Pixels" which supposedly help the iPhone "focus faster and better." Apple has not yet been clear on what exactly they mean by "Focus Pixels." However, in their keynote, they mentioned that it's a technology that's found in DSLRs, and they also showed a demonstration of the iPhone's continuous autofocus. Both of those point to Focus Pixels being either phase detection or a hybrid autofocus that uses both phase detection and contrast detection. What does this mean and will it really do what Apple claims, or is it just marketing exaggeration?
Monday, August 25, 2014
This is just a quick post to give my opinion on the recently announced Sony a5100, from the point of view of a Sony a6000 user who takes candid family photos.
|Sony a6000 + Sony 35 1.8 OSS|
Saturday, July 12, 2014
This is the second part of our review of the Olympus Stylus 1 (the first part is here). This review is a work in progress (last updated: July 12, 2014) and I'll continue to update it to the extent I have time available.
In this part, I will discuss the image quality (lens and sensor), and some of the special features of the camera. However, before we dive into a discussion of these aspects of the camera, I will first discuss how I use it, which will put the camera's capabilities into better context.
I believe the unique selling proposition of the Olympus Stylus 1 is its portability and only secondarily its image quality. The truth is, if someone's priority is image quality, there are other cameras out there such as the Sony RX10, a DSLR or some other interchangeable lens camera with potentially better image quality. However, I believe people who choose the Stylus 1 do so because portability is an important and overriding consideration for them. In my case for example, portability allows me to bring the camera anywhere and discreetly take candid photos. For people like me, I am ok giving up some optical image quality if it allows me to maximize my shooting opportunities and improve my substantive image quality. It is in this context that I would like to analyze the Olympus Stylus 1's characteristics.
IMAGE QUALITY - LENS
DOF, blur and bokeh
In general, you don't expect blurred backgrounds from a point and shoot. However, because of the Stylus 1's larger-than-average sensor (which translates to longer actual focal length for the same field of view), large aperture, and long focal length, it is possible to achieve blurred backgrounds under certain circumstances. Roughly speaking, at f/2.8, a background at least 10 feet away, and a laptop-viewing size, it is possible for the background to be at least slightly blurred when the subject's face occupies about 1/4 of the uncropped frame (based on the combination of focal length and subject distance). In the shot below, I was using only 12mm (55mm equivalent) but there some slight background blur because I was close enough to the subject and the background was far enough behind the subject.
At longer focal lengths, a blurred background is possible with less stringent conditions. In the shot below, I used an equivalent of 300mm focal length and aperture of f/2.8. My daughter's face occupies only about 1/10th of the frame (IIRC, I was about 20 feet away from her), but the background is at least slightly blurred.
|300mm, f/2.8, 1/500, ISO 100 (JPEG from camera with minor edits)|
Alternatively, at 300mm, it is possible to get a very blurred background when I am closer to the subject (let's say around 10 feet) with the background 10 feet or more behind the subject. The challenge is that at these distances there is noticeable compression, and the subject can look a little bit flat, especially when they are facing the camera at around a 45 degree angle.
|300mm, f/2.8, 1/640, ISO 100|
For shots where there is background blur, the bokeh (the quality of the blur) is usually pretty smooth. Difficult backgrounds such as long, thin objects (e.g. branches, bars) look reasonably smooth and not distracting. See the shot below.
|240mm equiv., f/4.0, 1/2000, ISO 100|
|For comparison: Nikon 85 1.8G bokeh of foliage|
Although the Stylus 1's bokeh does not have outlining, one issue it does have is something akin to onion bokeh. Onion bokeh is when out-of-focus spots of light appear to have fine concentric circles in them. Onion bokeh tends to appear in lenses with aspherical elements, though lenses without such elements can also be affected, and there are some lenses with aspherical elements yet don't have noticeable onion bokeh (e.g. Sony RX1). In the case of the Stylus 1, it does have an aspherical element and does have something like onion bokeh:
Fortunately, in the real world, this is rarely an issue. I have over 10,000 shots on the Stylus 1 so far, and the only "real world" shot where it is observable is in the shot above (shown again below for convenience), where the onion effect is visible on the large flare spot on the lower right side of the shot:
For smaller prints, the Stylus 1 is sharp enough in my opinion. If you're a pixel peeper though or you want to make very large prints, I think this is not the camera for you. For the rest of us, the Stylus 1's sharpness is not an issue.
Distortion: at 28mm equivalent, there is noticeable barrel distortion. This is not a problem for human subjects but may be an issue for architecture and cityscapes with lots of straight lines.
Flare: The lens has very good flare resistance even though it is not immune from flare. When there is a strong light source in the frame, there is sometimes a flare blob, although the contrast usually remains normal. In a few cases with very strong light, the contrast is reduced in areas of the frame near the strong light source.
Chromatic aberration: chromatic aberration is well controlled, although there is a little bit of fringing in areas of high contrast, when viewed closely.
|Chromatic aberration visible as purple fringing around the specular highlights of the berries in the foreground, and the green fringing around tree branches in the background|
IMAGE QUALITY - SENSOR
High ISO Capability
DXO rated the Stylus 1 at 179, slightly below sensor of the Olympus XZ-2, which was rated by DXO at 216 ISO (meaning at 216 [real not nominal] ISO, it has a signal-to-noise ratio of 30dB). By comparison, the Panasonic FZ200 is rated at 114 ISO, meaning the Stylus 1 has around 2/3 stop less noise than the FZ200.
In practice I find that 3200 ISO is acceptable (but please note I'm not a pixel peeper, and I usually view my images no more than 12 inches at its long edge). By acceptable I mean the color is still reasonable, and there is sufficient amount of detail. The image has quite a bit of noise but it can be mitigated with moderate noise reduction. This is about a one stop improvement from the LX5, which I tried to limit to 1600 ISO.
|3200 ISO (no noise reduction)|
|3200 ISO - 100% crop from raw (Lightroom 5 defaults), no noise reduction.|
I try to avoid 6400 ISO -- even 5000 ISO looks noticeably better than 6400 ISO.
|5000 ISO, f/2.8, 1/250, 300mm equiv. +25 noise reduction in Lightroom.|
|6400 ISO, f/2.8, 1/250. No noise reduction.|
|crop from adjusted shot|
Here are some more sample shots from the Stylus 1. As you check them out, you may want to consider whether having a camera with a larger sensor would have made much of a difference.
ISSUES / SUGGESTIONS FOR OLYMPUS
Here is my wish list for the Stylus 1.
1) When zooming, instead of showing the magnification, I would like to see the 35mm focal length equivalent. I think the buyers of this camera are not average consumers and Olympus doesn't need to try to impress them with zoom magnification numbers. Even better if Olympus can include a step zoom option for common focal lengths like 35, 50, 85, 105, 135, etc.
2) Enable Auto ISO in manual mode. The EM5 allows this, so can they allow it for the Stylus 1 as well? Better yet, include exposure compensation (for auto iso in manual mode) as well.
3) Change the live histogram so it's like the one from the EM5. Right now the histogram disappears while I'm making adjustments such as exposure compensation. It's hard for me to expose to the right with the histogram.
4) Can they enable the other options for Fn1 just like Fn2?
5) Can they include a touchscreen button for movie recording, so that if I use the Rec button for another option (e.g. zoom framing assist), I can still take a video using the touchscreen (maybe from the Super Control Panel)? Or maybe allow an option to start video recording using the menus.
6) The Stylus 1 disables the flash in Super Macro AF mode. Olmypus should allow the flash to be used even in Super Macro AF - at least as a wireless flash commander.
One way to view this list is that these are what I think are the biggest gripes that I have with the Stylus 1. As you can see, they're not that significant especially when compared to the Stylus 1's strengths which I've already noted in Part 1. In summary, if you want a camera with a very versatile focal length range, and you want it to be portable, and you're not a pixel peeper, I would recommend the Stylus 1.
Friday, June 13, 2014
|Stylus 1. f/2.8, 1/80, ISO 400|
About the shot above: My daughter gave me an art project from school, which I promptly attached to my file cabinet at the office. I took a shot with my Stylus 1 (which have with me almost all the time), then uploaded the shot to my phone via the Stylus 1's Wi-Fi function. I adjusted the exposure through Adobe Photoshop Express on my phone then shared the shot with my wife.
Monday, June 9, 2014
It has been a long time since my last post, and I am sorry for for not giving prior notice, but I have been traveling ever single weekend for the past month, and I still have a couple more weekends to go, this kills any spare time I have for posting here, but I am able to squueze some time to share a few fun photos with you. As you might notice, I don't have my regular signature on the photos, and the photos are larger than usual (do click them to see a larger version), the reason is that I have prepared all this post on the iPad, the collages in this post (with the grungy color effects below) were prepared using Autodesk's Pixlr+ app, resized to 2500px, and uploaded and posted using the Blogsy app.
Wednesday, June 4, 2014
Saw this deal from Groupon:
Some reasons you may be interested in the Nikon J1:
- hybrid phase detection and contrast detection with 73 AF points.
- Its continuous burst also allows for up to 60fps shooting at full resolution, though with autofocus locked. With autofocus, it can still shoot at 10fps.
Drawbacks include the limited and relatively pricey lens selection, and very slow 1/60 sync speed. The J1 also lacks a hotshoe.
Disclaimer: I'm not affiliated with Nikon or Groupon. Caveat emptor.