Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The intracies of modern camera lens repair (2024)

salvagedcircuitry.com

Post reply on HN
Print view View original

51–60 of 88 posts

Re: The intracies of modern camera lens repair (2024)

#51

Post by superjan »

josephg wrote: post #24
makeitdouble wrote: post #3

For those who haven't followed the camera world for a while, at this point a lens for a mirrorless camera will have a USB-C port to receive firmware updates. Tamron lenses for instance will allow a wired control or a wireless dongle to communicate with an app/computer and change the lens behavior, switch what the physical buttons and rings do. Potentially you can manage stepping through settings for stop motion like…

This is only true for photography. For some reason, cinema lenses are still - for the most part - purely mechanical. For film and TV, most camera operators still focus manually - often via gears attached externally to the lens. Coming from modern photography, manual focusing is inconvenient and difficult to learn. But there's something very old-school cool about cine lenses. They feel great.

When telling a story through film, changing what depth is in focus is a great way to move the viewer’s attention, without the need for cutting to a different angle or camera movement.

Re: The intracies of modern camera lens repair (2024)

#52

Post by dofm »

makeitdouble wrote: post #3

For those who haven't followed the camera world for a while, at this point a lens for a mirrorless camera will have a USB-C port to receive firmware updates. Tamron lenses for instance will allow a wired control or a wireless dongle to communicate with an app/computer and change the lens behavior, switch what the physical buttons and rings do. Potentially you can manage stepping through settings for stop motion like…

I would contend that if you were to pick a trend line in the last ten, twelve years it is actually the return of high quality, cutting edge manual focus lenses for stills photography, which was a negligible market by 2014.

Mirrorless has restored the utility of manual focus lenses in such a dramatic way that many of the significant advances in optical quality at every price point are happening in manual focus, and there is a real return to the understanding of the value of lens "character".

Time will tell how much of this is a stepping-stone to Chinese manufacturers moving to AF lenses (which is definitely a part of it) but many of the best new lens designs are coming from the likes of Cosina-Voigtländer and various cinema-adjacent stills brands.

Re: The intracies of modern camera lens repair (2024)

#53

Post by blagie »

exmadscientist wrote: post #10

The TPS62140's 30ns propagation delay is not enough to blow a fuse. The first rule of fuses (which many modern engineers do not understand!), is that fuses are not there to save your parts, and they simply will not do that. Fuses exist to prevent fires. Even a fast fuse is very, very slow compared to semiconductors. I've seen transistors blow up to "protect" fuses . They're for stopping fires and preventing the slaug…

Only partially true.

In well-designed microelectronics, they will.

The standard circuit involves a fuse, a fast Zener clamp, and sometimes a small resistor (e.g. 1 ohm) and/or capacitor. The design parameter is that, with the current limit from the resistor, the Zener should not blow out before the fuse.

The resistor needs to be small enough to not lose a lot of voltage under normal operations, but to still protect the Zener during the short surge during which the fuse blows. For most microelectronics, that's not hard. A 0.5W USB device might have 100mA of current max, which across 1 ohm is 100mV, so negligible for most purposes.

With high-power devices, it gets more complex.

Of course, consumer devices (a) will never be fixed (b) don't sell on this (c) every penny counts, so there's no market pressure to do things right.

But that's how we used to do it, and how it's still done many places where things count. If I'm building a one-off or few-off, it definitely will have proper protection.

Re: The intracies of modern camera lens repair (2024)

#54

Post by Forgeties79 »

dofm wrote: post #52
makeitdouble wrote: post #3

For those who haven't followed the camera world for a while, at this point a lens for a mirrorless camera will have a USB-C port to receive firmware updates. Tamron lenses for instance will allow a wired control or a wireless dongle to communicate with an app/computer and change the lens behavior, switch what the physical buttons and rings do. Potentially you can manage stepping through settings for stop motion like…

I would contend that if you were to pick a trend line in the last ten, twelve years it is actually the return of high quality, cutting edge manual focus lenses for stills photography, which was a negligible market by 2014. Mirrorless has restored the utility of manual focus lenses in such a dramatic way that many of the significant advances in optical quality at every price point are happening in manual focus, and th…

Rokinon nailed their timing in particular in the 2010’s

Re: The intracies of modern camera lens repair (2024)

#55

Post by Forgeties79 »

josephg wrote: post #24
makeitdouble wrote: post #3

For those who haven't followed the camera world for a while, at this point a lens for a mirrorless camera will have a USB-C port to receive firmware updates. Tamron lenses for instance will allow a wired control or a wireless dongle to communicate with an app/computer and change the lens behavior, switch what the physical buttons and rings do. Potentially you can manage stepping through settings for stop motion like…

This is only true for photography. For some reason, cinema lenses are still - for the most part - purely mechanical. For film and TV, most camera operators still focus manually - often via gears attached externally to the lens. Coming from modern photography, manual focusing is inconvenient and difficult to learn. But there's something very old-school cool about cine lenses. They feel great.

Because typically we use (usually wireless) whips to control lens elements. The 1st AC ideally is on a dedicated monitor with the setup in hand to pull as needed while the cam op handles the physical camera and focuses on framing and any movement.

Re: The intracies of modern camera lens repair (2024)

#56

Post by dofm »

Forgeties79 wrote: post #54
dofm wrote: post #52

Earlier quoted context omitted.

I would contend that if you were to pick a trend line in the last ten, twelve years it is actually the return of high quality, cutting edge manual focus lenses for stills photography, which was a negligible market by 2014. Mirrorless has restored the utility of manual focus lenses in such a dramatic way that many of the significant advances in optical quality at every price point are happening in manual focus, and th…

Rokinon nailed their timing in particular in the 2010’s

LK Samyang, yeah, doing some great stuff. They also make some (all, maybe?) of the native lenses for the Cambo Actus, which is another mirrorless era winner.

Re: The intracies of modern camera lens repair (2024)

#57

Post by formerly_proven »

Kirby64 wrote: post #11
clnhlzmn wrote: post #6

Earlier quoted context omitted.

Because to control the autofocus motor and other features it makes sense to have a microcontroller in the lens. If you have a microcontroller in the lens you have software in the lens and if you have software in the lens you're going to need to update it. You could argue that the camera should do firmware updates but the manufacturers for (semi) open mounts like the ones Tamron is making lenses for don't want to have…

> If you have a microcontroller in the lens you have software in the lens and if you have software in the lens you're going to need to update it. No, no you shouldn’t. There’s no reason why a microcontroller should ever need its firmware updated. The only reason why you would need to update the firmware is to add features, which I guess is mildly interesting for the tamron, but like I said… you could handle all extra…

Most third party lenses reverse-engineer the AF protocol. They're going to need updates.

Re: The intracies of modern camera lens repair (2024)

#59

Post by exmadscientist »

blagie wrote: post #53
exmadscientist wrote: post #10

The TPS62140's 30ns propagation delay is not enough to blow a fuse. The first rule of fuses (which many modern engineers do not understand!), is that fuses are not there to save your parts, and they simply will not do that. Fuses exist to prevent fires. Even a fast fuse is very, very slow compared to semiconductors. I've seen transistors blow up to "protect" fuses . They're for stopping fires and preventing the slaug…

Only partially true. In well-designed microelectronics, they will. The standard circuit involves a fuse, a fast Zener clamp, and sometimes a small resistor (e.g. 1 ohm) and/or capacitor. The design parameter is that, with the current limit from the resistor, the Zener should not blow out before the fuse. The resistor needs to be small enough to not lose a lot of voltage under normal operations, but to still protect t…

That's a good design for input overvoltage protection (assuming I've drawn the correct schematic in my head). But it doesn't help against most other fault conditions, particularly anything to do with the load/downstream going short.

Really, if you care beyond "blow the fuse if something shorts", you need active current limiting. For common cases like USB ports, you can buy chips that do it cheaply and efficiently. There are also some textbook circuits, though they each have their pros and cons. No matter what, if you've got a pass transistor or switching transistor that's about to go seriously overcurrent, you have to do something about it with active parts -- fuses aren't going to get it done.

But defense in depth is always a good strategy, and fuses play a key role there. The active circuitry saves the rest of the design; if it can't get the job done, the fuse makes sure nothing burns.

Re: The intracies of modern camera lens repair (2024)

#60

Post by makeitdouble »

Kirby64 wrote: post #11
clnhlzmn wrote: post #6

Earlier quoted context omitted.

Because to control the autofocus motor and other features it makes sense to have a microcontroller in the lens. If you have a microcontroller in the lens you have software in the lens and if you have software in the lens you're going to need to update it. You could argue that the camera should do firmware updates but the manufacturers for (semi) open mounts like the ones Tamron is making lenses for don't want to have…

> If you have a microcontroller in the lens you have software in the lens and if you have software in the lens you're going to need to update it. No, no you shouldn’t. There’s no reason why a microcontroller should ever need its firmware updated. The only reason why you would need to update the firmware is to add features, which I guess is mildly interesting for the tamron, but like I said… you could handle all extra…

> Just give me a dumb lens that does exactly what the body tells it to do.

It's hard to convey, but for instance you can reverse the fo us ring rotation, which probably only resonates with people who had to deal with it daily.

Or you can adjust the ring travel.

Or make the focus ring work as an aperture ring instead. Or straight disable annoying buttons.

Up until now you'd have to go hunt the perfect lens where the maker was 100% on board with your preferences. Or adjust your whole shooting style to every gear you use.

Sure a camera body could handle every single settings of third party lenses. But given what we've seen these 2 last decades, I don't think there was any chance of that happening. Tamron is partly Sony owned and they still did it on their own.

Post reply on HN