Part I review of the Sony 24-240mm on the Sony A7R is at http://photoblog.velgos.com/2015/03/sony-fe-24-240mm-lens-initial-quick-review-sel24240
Part II review with the 24-240mm on the Sony NEX-7 is at http://photoblog.velgos.com/2015/04/sony-fe-24-240mm-lens-review-part-ii-sel24240
Part III of the Sony FE 24-240mm F3.5-6.3 OSS Full-frame E-mount Telephoto Zoom Lens Review. In this review I wanted to see how the 24-240 stacked up against my Sony 35mm f/1.8 prime lens on the APS-C sensor Sony NEX-7.
Sony 24-240mm (SEL24240) vs Sony 35mm F/1.8 (SEL35F18) on a Sony NEX-7
After I posted my first review of the new Sony 24-240mm I checked out other reviews and reader comments. Some people were saying that the initial 24-240 tests were looking pretty good while others were saying it’s not good enough for them and they’ll stick with their fixed focal length prime lenses. As I read more zoom versus prime comments I began to wonder how much of a difference there would be between the 24-240 and a prime lens. The last time I compared my 18-200mm to a prime it actually didn’t do too bad. So I decided to check the 24-240 against my Sony 35mm f/1.8 which is known as a pretty sharp lens.
Comparing the image quality of a general purpose zoom lens against a fixed focal length prime lens is somewhat unfair. By default, a prime lens will almost always have better sharpness, less distortion, and much better optical performance in just about every way. But, a prime lens can’t zoom. And that’s the main tradeoff. With a zoom like a 24-240 you get decent optical quality with the convenience of not needing to change lenses. With prime lenses you get excellent optical quality but need to switch lenses if you want a different focal length.
So the question becomes, is the quality difference so much better with prime lenses that it’s worth the effort of changing lenses instead of using one zoom lens to cover a large focal range? It depends on a person’s needs. If you’re a studio portrait shooter you may mostly use something like an 85mm f/1.4 and on the rare occasion you need to switch lenses it only takes a few seconds. For a landscape photographer, changing a lens during bad weather conditions may not be an option and could mean missing that spectacular blue light shot.
So let’s take a look and see how the 24-240mm and 35mm compare at 35mm f/8 on the Sony NEX-7. While this doesn’t compare different focal lenths it should at least give a general idea of how the zoom does against the prime.
Nothing scientific here. Just some informal testing. All images were shot in RAW using the Sony NEX-7 at f/8 and ISO100. Files were imported from the SD card directly into Adobe Lightroom. No changes of any kind are made. The images are straight out of the camera so you get to see all of the natural distortion, vignetting, and other characteristics. The images below are PNG screen captures from Adobe Lighroom so you’re seeing RAW images exactly as I see them. The NEX-7 was mounted on a solid tripod. Optical Steady Shot was disabled. A two second shutter delay was used to help minimize any movement.
Test Scene – Sony 24-240mm on a Sony NEX-7, 35mm, f/8, Full Image
Sony 24-240mm and Sony 35mm, 35mm, F/8, Center, 100%
At center, the Sony 35mm lens on the right is a bit sharper at center but not by much. The 24-240 performs pretty well here.
Sony 24-240mm and Sony 35mm, 35mm, F/8, Top Left Corner, 100%
At the top left corner the 35mm lens is noticeably sharper with more detail and contrast. I feel the 24-240 still has respectable performance here.
Sony 24-240mm and Sony 35mm, 35mm, F/8, Top Middle, 100%
Sony 24-240mm and Sony 35mm, 35mm, F/8, Top Right Corner, 100%
The 35mm lens on the right is sharper. The tree branches do a good job of showing the difference.
Sony 24-240mm and Sony 35mm, 35mm, F/8, Right Middle, 100%
At right middle the 35mm lens is sharper. Again, this is especially noticeable in the tree branches.
Sony 24-240mm and Sony 35mm, 35mm, F/8, Bottom Right Corner, 100%
At the bottom right corner the 35mm lens is slightly sharper.
Sony 24-240mm and Sony 35mm, 35mm, F/8, Bottom Middle, 100%
At the bottom middle the 35mm lens is slightly sharper.
Sony 24-240mm and Sony 35mm, 35mm, F/8, Bottom Left Corner, 100%
At the bottom left corner the 35mm lens is noticeably sharper.
Sony 24-240mm and Sony 35mm, 35mm, F/8, Left Middle, 100%
At the left middle the 35mm lens is noticeably sharper.
Sony 24-240mm (Left) and Nikkor 28-300mm (Right), 28mm, f/8, Top Left Corner
This image is from a different review I did. This is a comparison of the top left corner of the Sony 24-240mm on an A7R and the Nikkor 28-300mm on a D800. I included it to illustrate what I would consider a big difference in sharpness and general optical quality between two very similar lenses.
So when you look at the 24-240mm and 35mm comparison images, it might make more sense why I say “slightly” sharper in some places. Because overall, I’m not seeing a huge difference in image quality between the zoom and prime. Yes, I realize this is only comparing 35mm on an APS-C camera and that at different focal lengths on a full frame camera the results will be different. But, I think it would be hard to disagree that this is a decent performance by the 24-240mm.
In defense of the Nikkor 28-300mm, I’m not picking on it. The D800 definitely shows its weaknesses. Even though the corner doesn’t look good here this is barely noticeable on a large 40×60 inch print and not noticeable at all on a web sized image. So while image tests at 100% like this may be meaningful to judge overall optical quality, that may, or may not, indicate the perceived quality of the image where it ends up being used.
On the APS-C NEX-7 I think the 24-240mm performs pretty well. And compared to a sharp 35mm prime lens, I feel it has very respectable image quality. At center, the difference is minimal and almost unnoticeable. At the sides and corners, the 35mm f/1.8 is sharper but in my opinion the differences aren’t very much. Perceptions will vary from person to person. To some people the differences may seem big enough that they’ll only use prime lenses. To others, the difference may seem so minimal that the zoom lens will work for them. It all depends on what you shoot and what your expectations are.
I will still have multiple lenses including an ultra-wide zoom and a prime but I can see this 24-240 helping to improve my efficiency.
So what’s your take? Do you feel the image quality difference between the 35mm f1/.8 and 24-240 is big or small?