Jump to content

SpeedBooster Math


fuzzynormal
 Share

Recommended Posts

So, I was considering something as a new lens for interview set-up on my m43 cams.  Basically, I was thinking the Voigtlander Nokton 42.5mm f/0.95 might be a good choice.  Simple, straightforward, good FF focal equivalent of 85mm f/1.9 which would look pretty decent for a talking-head portrait shot.  However, that lens is a 1K buy.  

What about something on the budget side?  If I got a 55mm f1.4. and put a lens turbo speed booster adapter on a m43 cam, which has a .7 crop and a 1 stop increase, wouldn't I end up in with similar numbers to the Nokton?  Or not?  That's a $50 lens and a $150 adapter.  

Aside from the bokeh rendering quality/characteristics which would probably be better on the Nokton, seems like the $200 set-up might be close enough to what I'd like to use for interviews.

What happens to the DOF when using these adapters?  Anything significant there? 

Anyone try this in real-life --or has run the numbers in the past to offer some insight?  I'm not even really aiming to get something super-sharp when doing interviews, so soft edges are okay.  I can accept those sorts of adapter limitations, just kinda wondering about the FF equiv specs of that lens/adapater rig on m43.  

Thanks in advance...

Link to comment
Share on other sites

EOSHD Pro Color 5 for Sony cameras EOSHD Z LOG for Nikon CamerasEOSHD C-LOG and Film Profiles for All Canon DSLRs

the 42.5 0.95 has an ff equvalent of 85mm f1.9. A m43 camera with a speedbooster has a cropfactor of 1.5. so a 55 1.4 would have the ff equvalent  of 85mm f2.1. So they would be very similar. I would say that going with a 50 1.4 and speedbooster would be a smarter option because then you can use that lens on a sony, samsung etc if you desire in the future.

im not the best at english so i hope that made sense

Link to comment
Share on other sites

Your math is correct. In fact, the Voigtlander m43 lenses have become a lot less attractive ever since the Speed Boosters came out.

If you spend a few more $ for an original Metabones Speed Booster + a Nikon Ai-s 50mm/1.4, you will even end up with a better overall lens/better overall optics than the Voigtlander (which isn't as great as its price suggests).

Link to comment
Share on other sites

Metabones Speed Booster + a Nikon Ai-s 50mm/1.4

Well, my old 50mm Nikon looks like hell when shot wide open.  Too much CA and haloing.  Figure I can find something a little cleaner though and still affordable.  Lots of 50's out there.  Some FD glass perhaps?  Pentax SMC might be good too.  Might be tough finding an old lens that's sharp @f1.4, but I'm not going for a pristine image anyway, just something that holds together decently.

Link to comment
Share on other sites

Well, my old 50mm Nikon looks like hell when shot wide open.  Too much CA and haloing.  Figure I can find something a little cleaner though and still affordable.  Lots of 50's out there.  Some FD glass perhaps?  Pentax SMC might be good too.  Might be tough finding an old lens that's sharp @f1.4, but I'm not going for a pristine image anyway, just something that holds together decently.

​maybe you have the non ai nikkor 50 1.4? The ais version is as good as the new 50mm 1.4 G

Link to comment
Share on other sites

Bokeh and rendering, classic 50mm 1.4 tend to have very busy bokeh and ugly spherical aberrations, at 58mm it gets a little bit better, at 85mm it starts to get nice and at 100mm its perfect. This is with classic fullframe glass, but it also applies to modern stuff to some point.

 

Anyway, check flickr for lenses and decide for yourself.

Link to comment
Share on other sites

at 58mm it gets a little bit better, at 85mm it starts to get nice and at 100mm its perfect.

Right, but on a m43 sensor going through a speedbooster seems like bokeh would be affected in some regard.  Well, as you say, I'll see if I can;t track down that sort of combo via flickr.

Link to comment
Share on other sites

If you want a vintage lens around 50mm that's sharp at f/1.4, my highest recommendation goes to the Minolta Rokkor-X 50mm f/1.4 PG. Sharp as a knife wide open, great color and contrast, but with slightly busier bokeh than its 58mm brother. That one is softer wide open--kind of a glowy, fairy tale look--but it crisps up by f/2 and the bokeh's much nicer. both can be had between $50 and $75, and can be stuck on a generic Speedbooster for extra bokehliciousness.

Some of the Metabones SB shots I've seen have had busier/weirder bokeh than the lens on a straight adapter, but it's nothing huge if your base lens has nice OOF blur to begin with. Also, I must disagree with araucariaThere's no hard or fast rule on which focal lengths have the best bokeh because it differs wildly between different manufacturers' designs, and even between different designs by the same manufacturer! For example, Minolta's 85mm 1.7 has much smoother bokeh than the f/2. It's just something you'll have to research. Luckily, there's a ton of information available to those who know how to Google. ;)

I wouldn't worry so much about the exact equivalent f-stop calculations on your lenses. Smaller formats don't scale exactly to their FF equivalent counterparts. They render differently. Lenses around f/1.4-f/2 in the 50-85mm range will give you beautiful, shallow portrait shots if you know how to use them. 

Link to comment
Share on other sites

Smaller formats don't scale exactly to their FF equivalent counterparts. They render differently. Lenses around f/1.4-f/2 in the 50-85mm range will give you beautiful, shallow portrait shots if you know how to use them. 

​Indeed, and I already do this quite often.  

Seeing as how a speedbooster will get focal-length and f/stop numbers into similar territory as FF (or s35) equivalent counterparts, how it renders and bends the light differently is a  consideration.  Thanks for the other advice too.  

Link to comment
Share on other sites

Hallo Fuzzy,

 

I assume, you´re considerations are about video, right?

I did a 3min short with just one 28mm 2.8 FD lens last Sunday, with lighting, small beachtek soundpackage and so.

I must say, the 28 did great! It has a very pleasing rendering to my eye. Handling and built is beautiful.

It has only five aperture blades. To me Bokeh looks nice. The 50mm FD 1.4 has eight blades.

 

With a focal reducer, I´d get the sturdiest one possible I think. The 50mm FD is a heavy sucker.

I tested a Camdiox/Roxsen focal reducer a few days ago, and it was pretty loose on the m43 mount and

weird enough it almost didnt come off the camera, neither did the lens. The FD ring is also kinda tricky I guess.

 

best regards

Link to comment
Share on other sites

I assume, you´re considerations are about video, right?

​Yeah, strictly m43 vids; a set-up for interview shots.  Usually I carry around a FF Canon and a 50mm specifically for the talking head stuff, but was thinking about alternatives that might satisfy me --so I can stick with one cam throughout a shoot; interview and b-roll... and I like the longer portrait focal length, 70-85'ish-mm, so a 50 lens on a speedbooster seems intriguing.

Of course, the extreme shallow DOF of Full-Frame allows some ease when making interview shots looks really nice, so anything that gets me into a similar aesthetic would be the goal.  "Busy" bokeh is not a huge concern of mine, I'm not that discriminating.  Just knocking the background out of focus as much as possible is my main concern.

Sometimes I'll do interviews with my m43 45mm f1.8 Oly lens, and that's decent enough, but considering that with a m43 2x crop it works as FF-equiv. at f3.6 90mm, I'd like to try and go a little shorter and more "open" on the f-stop for interviews. 

The lens turbo is cheap as are FD lenses, so I might experiment and see.  It's not a hefty investment.  If I don't like it I can always re-sell I suppose.

Link to comment
Share on other sites

​Yeah, strictly m43 vids; a set-up for interview shots.  Usually I carry around a FF Canon and a 50mm specifically for the talking head stuff, but was thinking about alternatives that might satisfy me --so I can stick with one cam throughout a shoot; interview and b-roll... and I like the longer portrait focal length, 70-90'ish-mm, so a 50 lens on a speedbooster seems intriguing.

Of course, the extreme shallow DOF of Full-Frame allows some ease when making interview shots looks really nice, so anything that gets me into a similar aesthetic would be the goal.

The lens turbo is cheap as are FD lenses, so I might experiment and see.  It's not a hefty investment.  If I don't like it I can always re-sell I suppose.

I just picked up a Canon FD 28mm f2 for a decent price and let me tell you, it is a beautiful lens. With the fast aperture, you can get some nice bokeh and if you combine with a focal reducer and a normal adapter, you can get 2 good focal lengths out of it. The only problem I found with that lens, is that a lot of copies have haze. The first one I ordered, has it bad so I returned it. Luckily, a day later I came across another one in mint condition for less than the first one. 

Link to comment
Share on other sites

If you're looking for a nice midrange FD zoom... Try out the Canon FD 35-70mm f4 lens. Metal construction, compact, constant aperture, parfocal and it has a reputation as being as sharp as a prime wide open. And even at f4, it has some pretty nice bokeh. It's often overlooked due to the 35-105mm, but let me tell you... It is nice. 

Here's a quick and dirty lens test I did with the 35-70  

 

 

Link to comment
Share on other sites

Thanks.  I'm more of primes guy myself, but that lens on a speed booster could be a nice option for fast production during a narrative film shoot.  Lots of decent options with the FD's for sure.  

Yeah, I am a prime guy as well, but recently I have been adding a couple vintage zooms to my lens sets for that very reason. 

Link to comment
Share on other sites

If you're looking for a nice midrange FD zoom... Try out the Canon FD 35-70mm f4 lens. Metal construction, compact, constant aperture, parfocal and it has a reputation as being as sharp as a prime wide open. And even at f4, it has some pretty nice bokeh. It's often overlooked due to the 35-105mm, but let me tell you... It is nice. 

Here's a quick and dirty lens test I did with the 35-70  

 

 

​Wow, nice test! Parfocal (or close enough as makes no difference), very little breathing, and that great low-con FD look. 

I went with the 35-105, but now I'm considering replacing it with the 35-70. The 35-105's a nice lens and focuses relatively close but at the cost of being a fat as **** chunk of glass. Nice and fast on a speedbooster though, and that range can't be beat for run and gun. 

I'd like to try and go a little shorter and more "open" on the f-stop for interviews. 

​If you're looking for a shorter focal length with shallower DoF on M4/3, you might consider the 25mm f/0.95 from SLR Magic. It can be had for less than $500 used, it's incredibly well-built, and it has the nicest bokeh I've ever seen. A little low contrast and "glowy" at f/0.95, but better than the Voigtlander. It sharpens up nicely at f/1.4--and that's for stills. I happily use it wide open for 1080p video. If you'd like me to shoot some portrait tests for you, I can probably find some time later today if I can find a willing subject who isn't too hungover from 4th of July. In the meantime, here's a stills comparison against some vintage stuff and the Voigtlander. http://3d-kraft.com/index.php?option=com_content&view=article&id=137:adorable-25s-25mm-f095-speed-lens-comparison-on-lumix-gh3&catid=40:camerasandlenses&Itemid=2

If you want a longer focal length, SLR Magic offers a 35mm f/0.95 as well, and the 35mm f/1.4 has amazing bokeh too. Take a look at Flickr and see what you think. I'm a huge fan of these lenses for video, and recommend them to everyone shooting M4/3. Amazing bokeh, good sharpness, fast apertures, decent prices, and they have this inexplicable 3D look that's incredibly cinematic. It must have something to do with its sharpness characteristics combined with low global contrast, but it produces the closest rendering to actual PL cinema glass of anything in its market. 

Link to comment
Share on other sites

I have looked at the SLR Magic stuff as well.  It is nice.  But, since a speed booster and old glass will be less than $200, I think I'll stay on that pathway (for now).

However, maybe a few SLR Magic lens rentals in the near future would be worth the time and $$.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • EOSHD Pro Color 5 for All Sony cameras
    EOSHD C-LOG and Film Profiles for All Canon DSLRs
    EOSHD Dynamic Range Enhancer for H.264/H.265
×
×
  • Create New...