I've been recommending 85mm f/1.8 lenses for people starting out with the bokeh panorama technique for a long time because I had seen good examples from them. However, until last week I had not actually used one.
If you're not sure what 'Bokeh Panos' are go here.
I was initially put off of Sony's basic range of lenses by their (rather meh) FE 50mm f/1.8. After reading lots of positive things about the 85mm f/1.8 I decided to give them another chance and I'm really glad I did. It's not exactly small on the tiny A7 body, but at 845g it does make a noticeably lighter travel setup than most DSLR equivalents (Canon = 1164g / Nikon = 1100g). Shown below (just for fun) next to a Canon FD 85mm f/1.2 & A1 film camera - 1310g (Digital Canon 85/1.2 setup = 1735g).
Unlike the recent "Bokeh King" lens I posted about (Sigma 135mm Art), the Sony FE 85/1.8 is all about light weight for me. I wanted a light lens for travelling, so I could shoot bokeh panos when on holiday and for this purpose it fits my needs perfectly.
I started out shooting bokeh panos with an 85mm f/1.4 (61mm aperture) in 2009 and have been chasing larger and larger aperture lenses ever since. After that I switched to a 135mm f/2 (67.5mm). Then I bought an 85mm f/1.2 (71mm), which I used for a few years and was very happy with. Most recently I started using a 135mm f/1.8 (75mm). Technically it's possible to keep going. Here are some lenses with even larger apertures...
105mm f/1.4 (75mm) - expensive
135mm f/1.4 (96mm) - very expensive / heavy++
200mm f/2.0 (100mm) - very expensive / heavy+ / too telephoto
300mm f/2.8 (107mm) - very expensive / heavy+ / far too telephoto
200mm f/1.8 (111mm) - very expensive / heavy+ / too telephoto
500mm f/4 (125mm) - very expensive / heavy++ / far far too telephoto
400mm f/2.8 (142mm) - very expensive / heavy+++ / far too telephoto
600mm f/4 (142mm) - very expensive / heavy++++ / far far far too telephoto
The first one on this list is technically the best bokeh pano lens available in my opinion, but at twice the price of the Sigma 135mm Art lens (which has the same aperture size and slightly better image quality) it's hard to justify given that it's only slightly harder to use.
After that you can see why These options start to get silly and/or annoying to use for this technique (see complaints after each option). One problem is size and weight (making them difficult to use hand-held), but another is that they tend to be longer focal lengths, requiring many more images to stitch a reasonably wide effective field of view. Escalating cost is another crippling factor for most. All these negative aspects added together make them not only difficult to use but increasingly worse for this technique as well.
The Sigma Art 135mm f/1.8 is the best lens I've used for the technique, but pushing the scales at 1600g (inc. camera) I wanted a lighter option for carrying with me every day and travelling. The Sony FE 85mm f/1.8 lens is not the cheapest 85mm lens in the world (Nikon & Canon's options are cheaper), but it is less than half the cost of the the previous 85mm f/1.8 for the Sony FE mount (Zeiss Batis).
The big question was - could it keep up with the lenses I was used to? Over the Christmas holidays I got a chance to give it a good test. Most of these images are from a car museum (Haynes International). Here are the results:
The smaller 47mm aperture of this lens (compared to the bokeh monster lenses) means you can't get such an obvious effect from a greater distance. Focusing at more than 3m begins to deminish the extreme effect (slightly depending on how wide your final image is). This is generally fine for smaller subjects, like people and car interiors. Larger objects like trucks, diggers or trains likely won't do well. The crossover point seemed to be for car sized objects.
The extreme effect is still possible, you just have to be careful with your focus distance and the final FOV (equivalent lens). If you want to push the shallow depth of field effect to its limits I suggest using a viewfinder to frame your subject before you start shooting for the panorama. Use no more than a 24mm, get as close to the car are you can and focus on details that are closer to you (like the badge from the front, for example).
To say that I'm happy with these results would be an understatement! I can wholeheartedly recommend this as lens as a great option for shooting bokeh panoramas. Not just for people starting out, but for advanced and even pro users as well. You can get twice the effect with an 85mm f/1.2 lens, but the weight of carrying that around with you all day is really noticeable by comparison. Many manufacturer's make a version of the 85mm f/1.8 lens and to a very high optical standard. Most are very reasonably priced too (especially second hand).
The 85mm focal length is probably my favourite / most used lens* because of how much I use this technique, although not everyone will want to take panoramas as much as I do. However, the fact that it's fairly reasonably priced (for what it is) and is a standard portrait lens also makes it easier to justify.
* Although the 85mm FOV is my most used for shooting bokeh panos, I believe that the ideal would be 105mm. The reason for this is that 85mm lenses have a bit too much distortion (for aligning images for stitching) and 135mm lenses requires too many images for the stitch. Thus something between these two focal lengths would be ideal. The reason I don't use one for shooting panoramas is that I don't have any with large apertures, they are kind of rare. The Nikon 105mm f/1.4 has about the biggest aperture of any from this range, so would be THE ideal bokeh pano lens, but the down side is mostly price (at around £2000). The weight is also pretty high (1.1Kg), but it's slightly less than the Sigma 135mm f/1.8 (which has the same sized aperture), so you can't complain too much about that.
It's worth noting that you can get a more extreme effect (than an 85/1.8) from a 135mm f/2 lens. This can be done on a similar budget with the Samyang (Rokinon) manual focus lens. This is a lot harder to use however (especially on a crop sensor camera) due to the extra images that it requires to get decently wide equivalent FOVs after stitching. Thus I would not recommend it over the 85/1.8 for people starting out, or with crop sensor cameras.
To see some of these images at higher res / quality you can see my Flickr collection here.