Gear Review: Sigma 18-35mm F1.8 zoom on Metabones Speedbooster XL (0.64x)

Written by Grant

In the last post I made, I went over all of the native micro4/3 lenses that we have, which I feel do an excellent job of covering most of the focal range, although there really isn’t much there to cover anything wide angle, just the Rokinon 12mm and the kit lens. Since then, I decided to pull the trigger on something I’d been considering for awhile: a Metabones Speedbooster focal reducer, and now I can experiment with adapted lenses! The main lens that I had in mind to use with the focal reducer is the reasonably priced and very well regarded Sigma 18-35mm f1.8 made for APS-C sensors.

So… it’s not a small lens, and it isn’t light either, but it balances just fine on the G9

The main item I had to consider was to go with the regular speedbooster which provides a 0.71x magnification which is what would generally be recommended for APS-C lenses, or the more extreme 0.64x ‘XL’ option, which is intended only for condensing the image circle of a full frame lens down to micro 4/3 dimensions. If life were black and white it’d be a pretty straightforward decision, but the difference between the 0.64 and 0.71 is 1/3 of a stop of aperture, which would go a long ways to adding versatility to my camera: letting me keep a compact kit when I want, especially for the telephoto stuff, but giving me closer to full frame results when I’m willing to use the bigger/heavier lenses (bringing me up to 2/3 of a stop slower, instead of the 2 stop disadvantage without the focal reducer).

The primary concern for using the XL with a lens that is too small for it would be some severe vignetting. It was easy to look around and find a ton of people using the combination of the speedbooster XL and the 18-35, as it is extremely popular, and adapts to a 11.5-22.4mm f1.1 zoom, but almost everything I could find about it was specifically talking about video, and cropped down to a 16:9 aspect ratio, and the best I could find about stills was along the lines of “it vignettes at the wide end, but goes away pretty quick as you zoom in”. So after finding a good deal on a used lens, I wanted to do a bit of testing with it, and share the results of the lens at different zoom/aperture/focus positions. All the pictures are RAWs straight out of the camera, with no adjustments or corrections.

Vignetting:

First up, at the wide end, and minimum focus distance:

11.5mm f1.1 (23mm equivalent, f2.2 depth of field)

There’s some very strong vignetting in the corners, for whatever reason, the bottom right is the most severe. I’ll show full stops increments from f1.4 to f8, and then the smallest aperture f10

f1.4, a lot of the lighter vignetting is greatly improved, but a very small black corner remains on both sides up top and bottom left, while a large dark corner on the bottom right remains
f2, still some small dark corners except for bottom right which is still decently large. It seems like the top left is the least severe as well, so it would appear that the lens mount isn’t perfectly centered above the image sensor.
f2.8, solid improvement in the bottom right corner, with only small black areas remaining at the other corners
f4, top left is so close to being gone, top right is slightly larger but still quite small, bottom left is a little worse than top right, and bottom right is still improving with each stop
f5.6, personally I’d feel this is a manageable level of vignetting, nothing is too obtrusive, and with a little touching up and/or some minor cropping can take care of it
f8, actually a bit worse than f5.6
f10, worse still, to my eyes, about the same level as f2

Next up, still all the way zoomed out, but focusing farther away (focused on the snowman):

f1.1, some strong vignetting across a lot of the frame, and significantly worse than when focused up close, but at least its a fairly smooth transition to black
f1.4, cleared up a bit, but still very strong
f2, most of the transition has cleared up, leaving some dark corners that would definitely require some cropping
f2.8, about the same, maybe a little better
f4, continuing some small improvements, but for most uses, a small amount of cropping to get rid of the very corners would be in order.
f5.6, need to remember to give myself some space to crop…
f8, about the same as f5.6, maybe a small improvement
f10, a little bit better than f8, but really not much change past f4

So how about some other focal lengths? Zoomed in to an indicated 20mm (actually ~13mm/26mm in full frame terms:

13mm f1.1, a lot of vignetting wide open still, but the hard dark corners are greatly improved.
13mm f5.6, a bit of vignetting is still present, but not to an extent that I am at all concerned with. This is roughly the image you’d be cropping down to to clean up the previous images if you wanted to keep the 4:3 aspect ratio.

And just for funsies, a quick check back at the minimum focusing distance:

13mm f1.1, again a significant amount of light/moderate vignetting, but no hard corners
13mm f5.6, again just a bit remaining in the extreme corners, but nothing I’m concerned about
14mm f1.1, only the vignetting you’d expect to be present in a fast lens wide open
14mm f5.6, cleaned up very nicely at f5.6 (just using wide open and f5.6 as reference)

So for focusing up relatively close, I feel like the lens is completely usable wide open and zoomed out, or stopped down a bit if I want to get rid of most of the vignetting. For more landscape-oriented uses, a 3:2 crop gives perhaps a more familiar aspect ratio, and takes care of most of the vignetting, as seen below. For astrophotography, which I expect this lens will excel at, I imagine it would be more or less case by case, whether composition would work alright with the vignetting, or to go to a 3:2 crop.

11.5mm f5.6, cropped down to 3:2

Image quality

First, a couple images I took of the cat indoors when I first got the lens:

11.5mm f1.1 ISO1250, very impressed with what this lens can do inside a dark house

I’m extremely impressed with what this lens does, in addition to being a nice wide zoom range at ridiculously fast aperture, its also extremely sharp wide open, and while a wide angle lens isn’t what you’re going to grab to get some blurry backgrounds, I find the door to be pleasingly soft and just out of focus enough for Penny to really pop out of the image. Next are some crops of a couple of the images from above.

Get any closer to Penny and she’s either fighting you or sleeping on top of you… But it’d be hard to ask for a sharper lens than this.
13mm f5.6 from above

Lastly, another image I grabbed of the snowman before heading inside:

22mm f1.4

Focusing

I opted for the Canon EF version of the speedbooster and lens, so autofocus does work with the combination, and it actually works just fine on the G9. It’s not as fast as the Panasonic lenses that I have, but it is by no means slow, and seems to be just as accurate as any of the other lenses I have. This is also a lens with nice manual focus controls (one of the nicer autofocus lenses to manual focus, that I’ve experienced, if that makes sense), it has an AF/MF switch on the barrel (although I use the lever on my camera body instead) along with a dedicated indication of the focus range, and the focus ring is well sized and turns with a nice weight, and you can feel when you reach the ends of the focus range.

Conclusion

Overall I’d simply put that I am very happy with the purchase of the speedbooster and the lens. It is an extremely sharp lens, and the vignetting can be significant and severe, but I think the 0.64x speedbooster is absolutely the way to go, the extra speed and wider field of view is worth the tradeoff of some manageable or croppable vignetting.

Some of my favorite pictures we’ve taken so far (image samples/lens reviews)

Written by: Grant

For this week, I wanted to spend a bit of time looking back over the last couple years, and put together a collection of my favorite pictures we’ve taken. I deal enough with data analysis, numbers, and graphs at work, so I don’t find myself overly interested in taking that sort of approach here. Instead, I’d prefer to share some of my experiences and thoughts on each lens, along with some of my favorite images that we’ve taken with each.

The first thing that stood out, is that early on, when we were using auto mode, and letting the camera decide on all of the settings, is that the camera often did a pretty poor job of choosing settings… Pictures at f/9-f/11, with very fast shutter speeds, which needed the camera to be bumped up to ISO 2500-5000 for an alarmingly high number of photos… It was a transitional period getting used to the rest of the camera and pick up on some of the basics, and it wasn’t all bad, sometimes it happened to choose quite well! It was nice to go back through and see a much smaller Bashi, and how much better at some of this stuff we’ve gotten. I do need to apologize in advance though, there’s going to be a lot of Penny… Click on the pictures in the galleries to see them larger.

Olympus 14-42 f3.5-5.6 EZ

The kit lens is what lived on the camera almost all the time for quite awhile, but has been on there very rarely since we acquired a few more lenses. The lens is super compact, which is the biggest things it’s got going for it, but it actually can take some excellent and rather sharp images too, as long as you have enough light to make up for the slow aperture. I can’t say I like the electronic zoom, and its often a bit slow to autofocus, but this is a reasonable price to pay for the compactness of the lens. It really is a nice match for the small Olympus camera, and is great for keeping things light and simple (it deserves more use than I give it).

Olympus 40-150mm f4-5.6

The second lens we got initially with the camera, it might not be an amazing lens, but it *is* cheap, and covers a nice telephoto range. It is small and compact, and actually can be fairly sharp. It hasn’t really ever been used all that much, and that probably isn’t going to change, but we have gotten a few nice pictures with it.

Rokinon 12mm f2

One of the two lenses we picked up in ‘wave 2’, a fast wide angle lens that came used, and cheap. It’s all manual, but focusing is very easy at this focal length. This lens really hasn’t seen much use either, as I’ve so far found myself far more interested in telephoto lenses to wide angle ones, but it is nice to have on hand just in case.

Panasonic Leica 25mm f1.4

The other half of our second wave of lenses, also picked up used, from a wonderful local used photography store we have in Columbus. I went in hoping to find the Panasonic 25mm f1.7 because its cheaper and a bit more compact and came well reviewed. I got all the way out to the car after buying just the Rokinon before I talked myself into just spending a bit more money and going for it, so I went back in and picked up the fast prime lens. As soon as we got home and put this lens on the camera, I knew I made the right choice.

This. Lens. Is. Awesome.

One of my personal favorites

We were fortunate to have a weird foggy morning right after we picked up the lens, and these were some of the first pictures I took with the camera. The difference between the maximum f3.5 of the kit lens to the f1.4 of this lens absolutely blew me away, and it focus very quickly also. Most of all, I love how crisp and in-focus Bash is, while Kristen and Luka are nicely blurred (this is still very high on my favorites list, and that was an excellent morning for backyard photography).

We had taken some nice pictures with the kit lens, but the experience I have had using this lens, the colors, the ability to make the subject pop out of the background, and the sharpness, it really made me feel like what I was using was some pretty high end camera gear, and that I was actually taking some nice photos, beyond just something to share with family.

One of the big strengths of the micro 4/3 cameras, is the number of lens options you have at most focal lengths (except for long telephoto primes, but we won’t get into that), due to having both Olympus and Panasonic having put out full lens lineups that are fully compatible with each other (except for making lens + camera stabilization team up and work in tandem). Just for the 25mm focal length, assuming you want autofocus, you can choose from the Olympus f1.2 or f1.8, or the Panasonic f1.4 or f1.7. I’ve read wonderful things about the Olympus f1.2 lenses, but I’ve been quite happy with the Panasonic f1.4, which is substantially smaller (and cheaper).

Panasonic 35-100mm f2.8

This is Panasonic’s equivalent of a typical 70-200mm f2.8 full frame zoom lens. I may have said some excellent things about the 25mm lens above, but this lens is the best one we own, and it’s really not much of a contest. Unless I am going to be strictly indoors or in very low light, and I only want to take one lens, I wouldn’t think twice before putting this lens on the camera. The f2.8 aperture at both ends of the zoom (a very versatile and useful focal range) is wonderful for keeping the ISO down. This lens is light and compact (for what it is), it’s zoom mechanism is all internal so it doesn’t get any longer even when you’re all the way zoomed in, plus it is weather sealed and has built in image stabilization (which we kept turned off with the Olympus to let the camera do the work, but with the Panasonic G9, they work together). I honestly don’t see any downsides to this lens, other than that f2.8 on a crop sensor isn’t going to give you all that narrow a depth of field, so if you want a ton of super blurry backgrounds, you’ll want a faster prime in this range (coming up), or maybe you would be happier with a larger sensor camera.

Panasonic 100-400mm f4-6.3

This lens is big, it was expensive, and it’s a bit silly, but it also is what makes the micro4/3 camera 100% worth it for me. It covers the 200-800mm full frame focal range in something that I only think is big or expensive because I’m not actually dealing with full frame lenses. Its nowhere near the aperture of the 35-100, so you need to have a fair bit of light, and while its very sharp at 100mm, I can definitely tell it suffers a bit and is softer zoomed all the way in to 400mm. I can’t zoom in with lightroom and clearly see each strand of fur on Luka or Penny like I can with the 25 or 35-100, but its still pretty good (occasionally very good),

and considering that I’m shooting with an 800mm equivalent focal length lens, and its no big deal to carry around, I’m completely ok with that.

Voigtlander 42.5mm f0.95

Last but not least, or most recent lens is an all manual, exceptionally fast 85mm equivalent lens. This focal length is of course already covered by the excellent 35-100, but I did want a faster prime in the 85mm-ish focal range. The 3 lenses I considered were the Panasonic 42.5mm f1.2 Nocticron (which has a fun name and a cult following), the Olympus 45mm f1.2, or the Voigtlander. The Panasonic has been around longer and is regarded as one of the best lenses available, and the Olympus PRO lenses are by all accounts phenomenal pieces of glass, but there were a few reasons I opted for the Voigtlander…

  1. It was cheaper, especially second hand how I picked it up
  2. It has a faster aperture, this is a focal range I already have covered with the 35-100, so might as well go for the fastest one available
  3. Minimum focus distance. The Voigtlander has a much closer minimum focusing distance than the other options, making it excellent for close-up photography (and keeping me from thinking I need a macro lens)
  4. Manual focus. This feels out of place, but I did want to experiment more with manual focus, and I generally assume that a lens designed to be focused manually will tend to have better control and feel than an autofocus lens

Despite being a redundant focal length, the Voigtlander seemed to offer me the most upsides for me, and do the most to make up for some of the inherent shortcomings of the small sensor with the fast aperture with the narrower depth of field and letting me keep to a lower ISO in low light. It’s easy to just head out with the 35-100 and know that I’ll be well equipped for most things I might want to take a picture of, but sometimes that feels a little bit too easy. Occasionally it is nice to just toss the manual lens on and be forced to slow down a little, and work a bit more to get the shot. Some of them get away because I can’t keep up with the focus, but I find I enjoy the ones that I nail a bit more, either because of some character of the lens, or the shallower depth of field, or because I feel like I was more involved in taking the picture (while the 35-100mm is absolutely our best lens, this one might be my favorite).