Earlier today, Frederick Van Johnson and I recorded a pilot for a new series from This Week in Photo. The series is tentatively called All About the Gear and the pilot episode is The Olympus OM-D vs Sony NEX 7 – Is Mirrorless More, or Less?
In the show I made the statement (at about the 8:00 mark) to the effect that the depth-of-field on a micro four-thirds (MFT) camera at a given aperture (say f/4) would be the equivalent of f/8 on a crop-sensor camera like the Sony NEX-7. What I should have said was that it would have been the equivalent of f/8 on a full-frame (FF) body. That’s what happens when you try to talk faster than your brain can operate.
In any case, in the YouTube comments, Jamie MacDonald challenged that statement, saying “f/1.8 is f/1.8 It is ‘sensor agnostic’ if you will.” Jamie is technically correct and I was taking a shortcut for the benefit of simplicity, for which I apologize. However this continues to be a much misunderstood issue, which I think deserves a more complete explanation.
Imagine you’re taking a picture of a tree with two cameras, both equipped with zoom lenses, from the same location. One is an MFT and the other is FF. Let’s assume both are set to an aperture of f/4. You compose your shot on the MFT camera and it turns out to require a focal length of 45mm. Now you compose the exact same shot on the FF camera. The tree is the same size (in terms of percentage of frame height) in both viewfinders. If you check the focal length on the FF camera, you’ll see it’s set to about 90mm. Same shot. Same aperture. Different focal lengths.
Now go home and look at both images. You’ll see that the image from the MFT camera has a much greater depth-of-field, while the one from the FF has much more boken, or blurring as you get away from the in-focus area of the image. Why, because of the difference in real focal length as opposed to equivalent focal length. (We say that 45mm on the MFT camera is the full-frame equivalent of 90mm because of the size of object in the frame from the same distance.)
As Jamie correctly points out, this is not actually due to the aperture, since it’s the same in both cases. But here’s the thing: If instead of shooting the FF image at f/4, you use f/8, now you would find the depth-of-field in the resulting images was nearly identical.
The superzoom on my big Nikons is 28-300mm. An equivalent superzoom on an MFT camera is 14-150mm. Those lens/camera combinations give me the same image-area range. I most-often shoot in aperture-priority mode, so with my FF camera I might decide to use f/11 to give me the desired depth-of-field for a particular shot. In order to get the same depth-of-field using the MFT camera, I need to set it to f/5.6.
So what does this mean in practice? When using lenses of equivalent focal lengths such as the kit zooms on each, to get the same depth-of-field as a full-frame camera, you need to use an aperture about two stops wider on an MFT camera and about one stop wider on an APS-C crop-sensor camera.
Hope that helps.
And please: give us feedback on the new show. Here, on the TWiP blog or on the YouTube channel.
In the first part of my review I compared the bodies of the Sony NEX-6 and NEX-7. As I mentioned then, my motivation for these reviews is to find the best way to “travel light” for a non-photographer’s trip to Turkey in June. I already own an NEX-7 with two lenses, but I wanted to (a) check out the NEX-6, and (b) find the best suite of lenses for this non-assignment. This post is all about the lenses.
Here are the six lenses I’ve used for the past four days and my comments on each:
- 18-55mm f/3.5-5.6. It’s a good-enough general-purpose lens, which I purchased as the kit lens for my NEX-7. Not particularly sharp and certainly slow, but it’s helped me get some decent shots over the past year.
- 16-50mm f/3.5-5.6. This is the newer kit lens for the less-expensive NEX bodies, and it’s weird. I wasn’t impressed. It’s a pancake-style zoom and takes about two seconds to expand after the camera is switched on. Seems like forever. It also has a fly-by-wire “power” zoom control, which is great for smooth zooms in video but it has an annoying lag for still images. If you’re buying an NEX camera, I suggest you not buy this lens with it unless you try it out first.
- 50mm f/1.8. I’ve owned this lens for the better part of a year. Even though it overlaps the 18-55mm in focal length, it’s sharper and faster than the kit lens. I pop it on when I need to grab more light (3 stops faster than the zoom), want the shallower depth of field or have time to take a more-careful shot that would benefit from a sharper lens.
- 16mm f/2.8. An inexpensive prime, but disappointing, particularly when compared to the alternatives. The interesting thing about this lens is that you can buy two adaptors for it. One converts it into an even wider-angle lens (about a 12mm) and the other gives you a fisheye. I didn’t test with either of these adaptors, but I may do so in the next month or so.
- 24mm f/2.8 (Zeiss). By all others’ accounts this is the killer lens for the NEX E-mount cameras. Now that I’ve tried it, I agree. Expensive ($1,100) but gorgeous. Sharp, high-contrast, minimal chromatic aberration. At a 36mm full-frame equivalency, this is a terrific lens for both general and high-res use.
- 10-18mm f/4. This one is my new discovery. I’ve started shooting more with wide and ultra-wide lenses and this really fits that niche. At a full-frame equivalence of 15mm-27mm, it’s reminiscent of my Nikon 14-24mm f.2.8. Well, not nearly as spectacular, but the 10-18mm does a pretty good job considering its size. Still, it’s a bit larger and more expensive ($850) than most other lenses listed here. But I do like it.
Two lenses (the 16-50mm and the 16mm) didn’t make the cut. Here’s the plan for what I’ll be taking to Turkey, at least as of now:
- 18-55mm f/3.5-5.6
- 10-18mm f/4 (rented)
- 24mm f/1.8 Zeiss (rented)
- 50mm f/1.8
Here’s my logic. The 18-55mm is fine as a walkaround casual lens when I’m outdoors in the daytime and not in my serious-photographer role. The wide-angle 10-18mm zoom is a perfect compliment to the kit lens with the crossover between them at 18mm (27mm full-frame equivalent). But when I move indoors, need more light and don’t want to crank up the ISO, or when I simply want to spend more time on a subject, I find I switch to the 50mm or the Zeiss 24mm primes.
The only lens I’m missing in this set is something telephoto. The 18-200mm superzooms (11x) are just too large to meet my “travel light” criterion. But with a 24MP sensor on the NEX-7 I always have the option of cropping. If I shoot at 55mm and crop 2:1, it’s the same as though I had used a 110mm lens, which is the equivalent of 165mm on a full-frame camera. And I still end up with a 6MP image, which is fine for posting online and prints up to 8×10.
If you’re thinking of buying one of these bodies or lenses (or any others for that matter) I strongly recommend renting first. Personally, I use BorrowLenses.com, but LensRentals.com and even your local camera shop are good, too. For example, the two lenses I’m taking to Turkey that I don’t already own would cost me about $2,000 total to purchase. To rent the pair for four weeks will cost me only about $225.
There are always surprises with gear. There’s always something the reviews didn’t tell you or you just missed. Rent for a 3-day weekend and it won’t cost you much. I think you’ll be glad you did.
[Spoiler alert: If I had to buy today, I’d go for the NEX-6 over the NEX-7. (Yeah, I know: I’m in the minority on this one.) But if you can wait two months, the rumors are that there will be an update to the NEX-7 that will hopefully tip the scales in that direction.]
I’ve been shooting with a Sony NEX-7 on and off for nearly a year, alongside my big Nikons. (See my earlier NEX-7 review.) Although I think of the Nikons as my serious cameras, the fact is that when I looked back at the end of 2012, many of my best images were captured with the NEX-7.
When I leave home for a shoot (even a photowalk) I tend to take at least one body and far more lenses than any reasonable person would be willing to lug around. For a recent trip to Death Valley, I even brought along two tripods. (How dumb is that?) But my wife and I are taking a non-photographer’s trip to Turkey in June, and I’ve decided I want to try traveling really light. As frightening as that sounds — and it does, to me! — it means leaving the Nikon bodies and glass at home. I’m already losing sleep over this. It’s not about the gear. It’s not about the gear…
Since buying the NEX-7, I’ve often wondered if I might have been better off with a micro four-thirds camera. So many friends love them. So I got my hands on an Olympus OM-D E-M5 for a review. Bottom line: Although I made the mistake of testing the OM-D with inferior lenses, I certainly didn’t like the camera any more than I like the NEX-7. The one advantage of the OM-D was the array of superior lenses (which I didn’t test!) for the micro four-thirds system. Sony has been properly criticized for a lack of good ones.
But in the past year Sony has released new lenses. I’d also read positive reviews of the newer NEX-6 and was curious how it stacked up to the -7. And that’s the genesis of this review. I wanted to check out the -6 and some better lenses, ultimately to decide what to take to Turkey. I’ll cover the bodies in this review and save the lenses for a separate post.
Take a look at the DxOMark comparison of the two cameras’ sensors. They’re about as close as they could be, and that confirms my subjective experience. Although the NEX-7 is 24MP and the NEX-6 is only (!) 18MP, they’re both excellent. If anything, 24MP is a bit much for casual photography, particularly if, like me, you always shoot in RAW mode. (I know that five years from now that will sound ridiculous.) If image quality isn’t enough to differentiate these two bodies, what is?
The advantages of the NEX-6 are:
- A dedicated Mode dial. This is personal preference, and I like this traditional approach. I do tend to change modes fairly often, so this works for me. Because the menu system on both these cameras is simply awful, the big issue is whether I can avoid the menus as much as possible. The NEX-6 allows me to change the important stuff without taking my eye away from the viewfinder: mode, aperture and/or shutter speed, ISO and exposure compensation. The NEX-7 just gives me two different ways to change exposure compensation by adding an extra control.
- Quick Navi menu. Available by pressing the Fn button, this bypasses that awful menu system to get you to the most-frequently needed functions. Plus, you can change (up to a point) which functions appear here.
- Less vulnerable controls. For some reason, I move the NEX-7’s controls accidentally more than I do on the NEX-6. I can’t explain why.
- Superior autofocus. The NEX-6 (and hopefully the replacement for the NEX-7) adds a 99-point phase-detect autofocus array and it really works. This gives the camera faster and more accurate autofocus. If you’re a video shooter — I’m not — this will be important to you since the phase-detect autofocus is even working in video mode, unlike a DSLR. Note that phase-detection autofocus only works on lenses that can support it and in some cases you need to update the firmware in both the body and the lens. In my tests, it worked on the 10-18mm, 18-55mm, 16-50mm, 50mm and 24mm, but not with the 16mm f/1.8.
- Standard hot-flash shoe. The NEX-7 has one that’s proprietary to Sony. (When will they ever learn?)
- WiFi. You can use WiFi to copy images to a computer or mobile device or to upload them to Facebook, but it’s a pain to do so.
- Downloadable apps. Available from Sony’s online store, the apps are free or cost $4.99. It looks like a few of them could be useful, but I didn’t test them.
- Lighter by 20%.
- Cheaper by $250 at today’s street prices.
So what’s so good about the NEX-7?
- Larger, better sensor (but not by much).
- Tri-Nav controls. Two soft/configurable controls on top versus only one on the -6. As I wrote above, pure personal preference.
- Battery Life. Probably because of the NEX-6’s WiFi and perhaps the phase-detect autofocus, the NEX-7 battery life is a bit better, rated at 430 shots versus 360 shots for the -6.
- External mic jack for video shooters.
- 3D photos for display on your 3D TV. We all have 3D TVs, right?
- Very slightly smaller, even though it’s somewhat heavier.
As I think you can see, my feelings are that the NEX-6 is, overall, a better camera with the most important differences being the controls and the improved autofocus. I’m not switching from the NEX-7 now, but if Sony combines the best of both in an updated -7, I’ll probably bite.
Here’s Part 2: Sony NEX: The Lenses