FS7: FE 28-135mm 1:4

C

camboy

Member
Hello,
as the sony FE 28-135; 1:4 is a fullframe lens, it seems useless for handheld filming with the FS-7.
not wide enough, and f-stopp 4 is also not so impressiv.
so why is metabones or sony not making an e-mount to e-mount speedboster?
focal lenght on the wide side would be acceptebal for handheld work, and it would turn it to an f-stopp 2.8
 
hello Grug,
what are you meaning by, where would the glass go ?
i am not an expert on optical adapters, i just thought if it works with EF lenses why shouldnt it work with oder fullframe lenses.
or is the emount flange focal distance the problem. please explain so i could learn about it
thank you very much for your answer.
 
You need space between the lens mount and the rear of the lens in order to fit the speedbooster glass. So if you have an e-mount camera and an e-mount lens there can't be any room for the speedbooster because the lens is designed to attach directly to the mount.

So you need lenses with a longer flange distance than the camera mount to create space for the adapter.
 
Keep in mind that in classic photography there were not digital image sensors or onboard LCD screens. An SLR camera body had a shutter installed at an angle with a mirror, which permitted the photographer to see the point of view of the lens. To take a photograph, the shutter and mirror had to flip up, sending light to the film instead of to the eyepiece (which was dark during the exposure).

That mirror assembly took space, as you can imagine, so lenses had to be designed with that extra focal plane distance considered.

Nikon G, Canon FD, and Canon EF were all lens mount systems originally designed for photographic film SLR systems, and making them work with digital sensors mostly required placing a digital sensor where the film had previously been.

Micro 4/3 and Sony E mount are lens systems designed for mirrorless cameras, where typically the digital sensor image is pushed to an LCD screen. Because they didn't have a mirror, the rear focal plane distance could be very short.

This is why, before we get into speed boosters, it's easy to make a Canon EF to Sony E-Mount adapter, but impractical or impossible to make the reverse. In fact, the former needs no glass - it just needs to be an empty metal tube that gives the Canon lens the right distance to focus on the plane of the image sensor of the Sony camera.

A typical Speedbooster takes advantage of this space where a mirror went to alter the optical path and enlarge the image.

An E-mount to E-mount speedbooster adapter is either impractical or straight up impossible, because there is no space to put the enlarger.

You can't get something for nothing when it comes to optics.
 
hello Grug,
thank you for the information.
i see clearer know.
Too bad, a speedboster would have made the 28-135 to a good run and gun lens.
 
I quite agree and have made that observation from day one. My calculations put the "kit lens" at an effective FOV of 40mm/190mm. Nice for an interview but virtually useless for hand held work. The f4 is tedious but as the camera has a lot of built in quiet speed, you are only a stop away from the Nikon 2.8 series of glass.
But at $2500 I think the better choice is the Sony SELP G 18-105mm zoom. It's bare bones but it does speak to the camera thus allowing all the auto functionality. It's a power zoom with an on lens rocker switch on the operators side. No on lens aperture and only fly by wire focus and zoom but using the 1.4x mm formula, you have an effective FOV of 25mm/147mm, which while is not ideal, is not a bad hand held option. The kit lens only focuses down to 3.3ft while the Sony G focuses down to 9 inches. Both are f4 throughout and hold zoom focus.
I tested both lenses side by side and could see no image difference between the two. The kit lens is $2500, the G lens is...$600. Works for me. Between the G and my Nikons, my Zeiss primes (all via Metabones Speedbooster), I'm good to go.
 
How does the old Sony 18-200 kit lens (silver, extending barrel) compare to these other lenses? What are its pros and cons when using it with the FS7? I know it's not great for R&G-- especially when compared to the lens that came with the EX3, for example-- but otherwise? Sharpness, etc.? .
 
Remember that the Sony SELP G 18-105mm zoom exhibits severe pincushion distortion. The FS7 corrects for this in most modes, but not, say, the Raw output with the back installed. Other than that, I hear it's a great lens.

I havn't used the 18-200 lens on anything except my FS700 (now sold), but I would describe it as a very good compromise lens. It's reasonably sharp, it has an amazing range, autofocus is so/so, but it's variable f-stop, and very slow on the telephoto side.
 
I had the 18-200 power zoom but sold it together with the EA50 it originally came with. Used it a bit with the FS700 as well.
I really miss that lens. It was often too slow but very versatile for live shows and had great auto focus (coupled with face detection) and great image stabilisation.
 
Viddovation said:
Keep in mind that in classic photography there were not digital image sensors or onboard LCD screens. An SLR camera body had a shutter installed at an angle with a mirror, which permitted the photographer to see the point of view of the lens.
Click to expand...

Nearly 100% of SLR cameras have a focal plane shutter, it is installed parallel to the film/image plane, not at any angle. Some SLR cameras and motion picture cameras do indeed have a mirror which doubles as a shutter but I don't know a single SLR or film camera where an independent shutter is mounted at an angle.
 
broughtonfilm said:
Nearly 100% of SLR cameras have a focal plane shutter, it is installed parallel to the film/image plane, not at any angle. Some SLR cameras and motion picture cameras do indeed have a mirror which doubles as a shutter but I don't know a single SLR or film camera where an independent shutter is mounted at an angle.
Click to expand...

If I have spoken inaccurately or in a misleading fashion, I apologize. To be honest, I've come of age with digital image sensors, so I get sloppy on old school photographic principles.

That said, broughtonfilm is correct that the mirror and shutter are generally separate, and that the shutter is usually not at an angle. However, relevant to the OP of this thread, the mirror is typically installed at a 45 degree angle, to move the lens image to the pentaprism and then to the eyepiece. This mirror obstructs the film and shutter, and has to move out of the way for an image to be exposed. The space this mechanism requires is why Canon EF and other lens format had to be designed with a deeper flange depth than new mirrorless systems like Sony E and Micro 4/3 were.
 
I don't know if it's because I work primarily in narrative. But I spend 95% of my time between 28mm and 135mm, and only really go wider when I run out of space. So I think the lens actually has a terrifically useful range for S35mm production.

Add one of the 18-35mm f/1.8 Sigma converted lenses and you're covered for 99% of things with just two lightweight lenses.
 
Viddovation said:
If I have spoken inaccurately or in a misleading fashion, I apologize. To be honest, I've come of age with digital image sensors, so I get sloppy on old school photographic principles.

That said, broughtonfilm is correct that the mirror and shutter are generally separate, and that the shutter is usually not at an angle. However, relevant to the OP of this thread, the mirror is typically installed at a 45 degree angle, to move the lens image to the pentaprism and then to the eyepiece. This mirror obstructs the film and shutter, and has to move out of the way for an image to be exposed. The space this mechanism requires is why Canon EF and other lens format had to be designed with a deeper flange depth than new mirrorless systems like Sony E and Micro 4/3 were.
Click to expand...

Yeah, it was nitpicking on my part. Otherwise your comment was a relevant explanation of limitations of a reflex camera system.
 
All of the above is true, never the less there is no reason why sony couldn't take whatever optical elements are used in a speedbooster and build them into the 28-135 and churn out an effectively 20-100 f2.8 with the same mechanical qualities. No doc. or newsshooter will ever walk around with a zoom lens that doesn't go wider than 28- yes if you do narrative then you don't need it- you can effectively work with a 35-50-85 but the rest of us do.

Sony would sell these like hotcakes.
 
Or just use it on an A7S, where the f/4 limitation is no issue and the wide end of the lens become a genuinely wide-angle.
 
the A7s is a nice little camera that should be used for its strengths: low light, low profile etc. It is not a primary acquisition camera.
 
I think Sony is aware that something widerwhat is desired for the FS7 and if its possible I wouldn't be surprised if they try to adapt the basic 28-135 by adding something like the speed booster optics to make it a wider 2.8 lens. Easy for me to suggest when I don't know didly about optics though.
 
Lenilenapi said:
I wouldn't be surprised if they try to adapt the basic 28-135 by adding something like the speed booster optics to make it a wider 2.8 lens.
Click to expand...

I'd put that possibility out of your mind. The 28-135mm is designed for an 18mm flange distance (e-mount), which leaves no room to wrangle a speedbooster-type optic on to the back of it. I'd say the best we can hope for is a matching wider-angle optic.
 
icarusfilm said:
All of the above is true, never the less there is no reason why sony couldn't take whatever optical elements are used in a speedbooster and build them into the 28-135 and churn out an effectively 20-100 f2.8 with the same mechanical qualities. No doc. or newsshooter will ever walk around with a zoom lens that doesn't go wider than 28- yes if you do narrative then you don't need it- you can effectively work with a 35-50-85 but the rest of us do.

Sony would sell these like hotcakes.
Click to expand...

I'm by no means an optical engineer, but I suspect this simply isn't as easily achieved as you think it would be.

The Sony lens weighs 2.7 pounds or so. Assuming your logic is right, and all we're missing is an inline speedbooster, we might as well consider that we have a hypothetical combined 3 pound lens, at T2.8, with a FOV for Super35 of approximately 18-85mm, and seeing as this hypothetical lens is made from the same parts as the current lens and a speed booster, it should cost no more than $3,000 USD.

The three modern lenses I could find with a similar field of view and speed all are significantly heavier, and also significantly more expensive:
ARRI/FUJINON Alura Zoom 18-80 - $20k+ used - T2.6 - 10.4 pounds (no power zoom included)
Angenieux Optimo 17-80 - $32k+ used - T2.2 - 12.1 pounds (no power zoom included)
Fujinon 19-90mm Cabrio - $40k new - T2.9 - 6 pounds

Essentially, the closest lens on the market to the specs that you would like weighs twice as much (6 pounds instead of 3), and costs $37,000 more.

If Sony actually could make the lens with the properties you're suggesting, they could charge $20k for it, and it would still sell like hotcakes.

Sadly, I think the truth is that it isn't as easily accomplished as it is imagined.
 
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