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Author Topic: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4  (Read 6400 times)

shadowblade

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Re: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4
« Reply #20 on: February 08, 2016, 12:56:51 pm »

Check out the latest TCS video at the Sony event. Jordan the video guy mentions that the new lenses are focus by wire.

That seems a bit odd.

Still, it matters much less for a mirrorless lens than for an SLR lens, since, without the camera being on, you can't see anything in the viewfinder anyway. As long as it's just as instantly responsive as a mechanical focus ring, and has the same tactile feel.
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Telecaster

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Re: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4
« Reply #21 on: February 08, 2016, 04:04:31 pm »

That seems a bit odd [focus by wire].

Sony is, among other things, aiming at eliminating mechanical complexity (and thus extra co$t) so IMO this makes sense.

-Dave-
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BernardLanguillier

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Re: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4
« Reply #22 on: February 08, 2016, 04:49:07 pm »

Sony is, among other things, aiming at eliminating mechanical complexity (and thus extra co$t) so IMO this makes sense.

Margins are an important target for Sony considering their overall financial situation. They aim for high value equipment selling at premium price with high margins. So it does make sense.

Besides, I believe that they designed these lenses under the assumption that they would be autofocused most of the time considering the advantages of mirrorless in terms of focusing (that I would summarize with eye detection).

Cheers,
Bernard

shadowblade

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Re: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4
« Reply #23 on: February 08, 2016, 08:30:04 pm »

Sony is, among other things, aiming at eliminating mechanical complexity (and thus extra co$t) so IMO this makes sense.

-Dave-

Focus-by-wire is adding mechanical complexity, not taking it away. You still have a focus ring. Only that, instead of moving the lens elements directly, turning it drives a motor that then moves the elements. Which requires more mechanical parts as well as more circuitry.

That's just another thing that can fail. I've had AF fail in a lens during a long trip before. Fortunately, I was able to MF for the rest of the trip and come back with great photos. Had the lens been completely unusable, I'd probably have abandoned the rest of the $15k trip and come home, since there'd be little point in continuing if I couldn't shoot anything. And, unlike bodies (where you will usually have a backup), you don't normally carry more than one of the same lens on a trip.
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Hywel

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Re: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4
« Reply #24 on: February 09, 2016, 08:58:59 am »

Have you had a look at http://www.lensrentals.com/blog/2015/12/sony-fe-35mm-f1-4-za-lens-teardown ?

It's fascinating. The Sony FE lenses genuinely do focus in a completely different way from everyone else's.

As Roger says, he doesn't know whether it is better or worse, and neither do you or I, and Sony probably don't know yet either.

But they are trying to do something different, and that's why these lenses are fly-by-wire: the lens elements are moved electro-magnetically instead of mechanically.

You are right that AF reliability might be an issue especially for long trips. I think unless I was really carting everything on my back the whole time I'd have a full backup with me, at least to cover my most common shooting lengths. A spare body with a 24-240 or 24-70 or whatever, or a Panasonic GH4 and 7-14, 12-35, 55-200 would probably be my minimum choice of backup on any significant trip. (Normally I take my Hasselblad kit, plus A7RII and 28, 55, 70-200. From now on I'll be adding the 24-240 as well).

I always try to avoid a single point of failure, so we try to travel with two MacBooks, enough cards to cover the whole trip if we can't offload, etc.. Batteries are about the only thing I don't take enough of to cover the whole trip (although maybe I should!)



Cheers, Hywel
« Last Edit: February 10, 2016, 05:12:56 pm by Hywel »
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ErikKaffehr

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Re: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4
« Reply #25 on: February 09, 2016, 05:03:24 pm »

Hi,

Everything can fail.

Now Sony's technology is new (at least in this context) so lesson will be learned.

There is a reason for using linear drives, CDAF requires very fast movement of the focusing element. CDAF is possible with normal focusing like USM but it would be slow.

Very clearly, USM/HSM/SSM lenses may focus manually if USM/HSM/SSM fails. But if aperture control fails the lens may also become less than usable.

Best regards
Erik

Focus-by-wire is adding mechanical complexity, not taking it away. You still have a focus ring. Only that, instead of moving the lens elements directly, turning it drives a motor that then moves the elements. Which requires more mechanical parts as well as more circuitry.

That's just another thing that can fail. I've had AF fail in a lens during a long trip before. Fortunately, I was able to MF for the rest of the trip and come back with great photos. Had the lens been completely unusable, I'd probably have abandoned the rest of the $15k trip and come home, since there'd be little point in continuing if I couldn't shoot anything. And, unlike bodies (where you will usually have a backup), you don't normally carry more than one of the same lens on a trip.
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Erik Kaffehr
 

shadowblade

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Re: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4
« Reply #26 on: February 09, 2016, 10:36:12 pm »

Hi,

Everything can fail.

Now Sony's technology is new (at least in this context) so lesson will be learned.

There is a reason for using linear drives, CDAF requires very fast movement of the focusing element. CDAF is possible with normal focusing like USM but it would be slow.

Very clearly, USM/HSM/SSM lenses may focus manually if USM/HSM/SSM fails. But if aperture control fails the lens may also become less than usable.

Best regards
Erik

Any reason why it can't be mechanically linked to a focus ring, rather than relying on an electronic link?
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ErikKaffehr

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Re: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4
« Reply #27 on: February 10, 2016, 01:10:29 am »

Hi,

The more things you add the more probable failure will be…

Most cameras today have electronically operated apertures, as electronic control is needed for fully automatic exposure. Also, we really want view and focus at full aperture and expose stopped down. So, some version of automatic aperture is needed and it has been a standard since 1960-es.

Just some oil on the aperture blades would stop the automatic aperture from working. To put it in perspective, I have been taking pictures since 1965 and had something like 50 lenses until today and aperture only failed in one. Bayonet needed replacement on a 1985 generation lens and automatic aperture failed on a Hasselblad CF lens I used to have. Other than that I had no lens repairs/failures.

I guess that modern lenses may be more prone to failure, though.

Lenses that are used stopped down all the time (like Leica M-lenses) may be less prone to failed aperture. But I know of some cases where Leica S system had malfunctioning apertures.

The way I see it, any component of any system may fail. 2012 I was on a trip to the US, my tripod mount on the 70-400/4-5.6 G got stuck and my brand new RRS tripod came all loose first day. I could repair both in the evening…

Best regards
Erik


Any reason why it can't be mechanically linked to a focus ring, rather than relying on an electronic link?
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Erik Kaffehr
 

Hywel

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Re: New Sony FE lenses - 24-70 and 70-200 f/2.8, and 85 f/1.4
« Reply #28 on: February 10, 2016, 05:19:12 pm »

Any reason why it can't be mechanically linked to a focus ring, rather than relying on an electronic link?

The way they have done it, yes. The lens element is purely a component in a linear electric motor. It isn't moved mechanically, it is moved directly by the action of an electro-magnet on the lens element.

That's not amenable to any sort of mechanical link. Because the lens element is moved directly by an electro-magnetic signal, it HAS to be fly-by-wire. You have to translate from any sort of physical mechanical control input to an electric signal, because the electric signal directly moves the focussing element of the lens.

It's not translating a physical movement to an electrical one then using a motor to rotate a traditional helical focus system. The electric signal moves the lens element directly.

Really, their only choice once they had decided to opt for that system was whether to provide a free-rotating ring, or provide physical stops. Presumably the free-rotating ring is easier for them to do, so they did that.

Cheers, Hywel
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