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Post by peterob on Jan 15, 2023 8:14:23 GMT
Seems curious that, to serve all this video stuff, they've had to introduce lenses that focus more slowly, or rather react to changes in plane of focus more slowly, because the built-in motors for stills use are too fast.
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Post by squeamishossifrage on Jan 15, 2023 8:42:08 GMT
Quite honestly I think you are on a hiding to nothing. Hold on there - I'm looking for information and opinions, not staking out a position. As I said, I have a mix of both types of lens, but have seen no particular benefit from lens AF versus body AF motors, including for sports. I regularly photograph show-jumping, motor rallies and the most challenging, kiteboarding. I have used both of my 70-300mm zooms for kiteboarding, where simultaneous zooming and maintaining focus on a 25mph moving target is essential, and I have never been aware of any focus lag or missed focus with either of them. I paid a 35% premium for the Tamron USD. Both lenses were purchased within a year of each other, and while the Tamron is sharper from 230mm upwards, the Sony is sharper everywhere else. I accept that for extreme telephotos where large lumps of glass have to be moved quickly for sport/wildlife, there is probably a speed advantage with in-lens motors, but for a 50mm f:1.4? I remain skeptical that there is, outside the categories mentioned, any real photographic advantage for most amateur photographers. The fact that in-lens motors are now the industry's focus does not bear on that. |
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Post by andy on Jan 15, 2023 9:02:15 GMT
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Post by geoffr on Jan 15, 2023 10:18:37 GMT
Quite honestly I think you are on a hiding to nothing. Hold on there - I'm looking for information and opinions, not staking out a position. As I said, I have a mix of both types of lens, but have seen no particular benefit from lens AF versus body AF motors, including for sports. I regularly photograph show-jumping, motor rallies and the most challenging, kiteboarding. I have used both of my 70-300mm zooms for kiteboarding, where simultaneous zooming and maintaining focus on a 25mph moving target is essential, and I have never been aware of any focus lag or missed focus with either of them. I paid a 35% premium for the Tamron USD. Both lenses were purchased within a year of each other, and while the Tamron is sharper from 230mm upwards, the Sony is sharper everywhere else. I accept that for extreme telephotos where large lumps of glass have to be moved quickly for sport/wildlife, there is probably a speed advantage with in-lens motors, but for a 50mm f:1.4? I remain skeptical that there is, outside the categories mentioned, any real photographic advantage for most amateur photographers. The fact that in-lens motors are now the industry's focus does not bear on that. In which case, I have given you my opinion, there is a real tangible advantage to in lens focusing motors, for the way I use them.
The need for fast focusing is driven by the subject, fast flying birds that change direction rapidly being particularly challenging. My 300 f4 with in camera focus drive can't cope, my 70-200 f2.8 with in lens motor can and does. Thus there is an advantage as far as I am concerned.
You have however missed the point I was, obviously, failing to make; specifically that proving an advantage is extremely difficult because we don't know what, if any, limitations have been placed on the in-camera focusing drive when compared to the in-lens drive using the same camera.
Some years ago I had a Tokina 70-200 f2.8 which was focused from the camera, when I swapped it for a Sigma equivalent with HSM I noticed an improvement in focusing speed. The cameras concerned were two Nikon F5 bodies, pedestrian by modern standards, I would not then have returned to a camera driven lens and certainly wouldn't do so now. Whether a more recent lens using the motor in one of my cameras would be as responsive as my current lenses is academic, nobody makes them.
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Post by squeamishossifrage on Jan 15, 2023 10:28:50 GMT
Thanks for that - a very interesting read. The statement " Over the next 30 years or so, it became clear that Canon’s designers had got it right" begs the issue of why they got it right - it is a rather unsupported statement in the context of the article. |
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Post by andy on Jan 15, 2023 11:14:34 GMT
Thanks for that - a very interesting read. The statement " Over the next 30 years or so, it became clear that Canon’s designers had got it right" begs the issue of why they got it right - it is a rather unsupported statement in the context of the article. Canon also have an interesting page suggesting that the lens motors allows faster autofocus and led to lenses like 300mm f/2.8. www.canon-europe.com/pro/infobank/usm-stm-lens-technology/Perhaps another advantage is with smaller lenses they can use smaller motors that use less power so batteries last longer. |
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Post by squeamishossifrage on Jan 15, 2023 11:38:50 GMT
In which case, I have given you my opinion, there is a real tangible advantage to in lens focusing motors, for the way I use them.
The need for fast focusing is driven by the subject, fast flying birds that change direction rapidly being particularly challenging. My 300 f4 with in camera focus drive can't cope, my 70-200 f2.8 with in lens motor can and does. Thus there is an advantage as far as I am concerned.
You have however missed the point I was, obviously, failing to make; specifically that proving an advantage is extremely difficult because we don't know what, if any, limitations have been placed on the in-camera focusing drive when compared to the in-lens drive using the same camera.
Some years ago I had a Tokina 70-200 f2.8 which was focused from the camera, when I swapped it for a Sigma equivalent with HSM I noticed an improvement in focusing speed. The cameras concerned were two Nikon F5 bodies, pedestrian by modern standards, I would not then have returned to a camera driven lens and certainly wouldn't do so now. Whether a more recent lens using the motor in one of my cameras would be as responsive as my current lenses is academic, nobody makes them.
I, on the other hand, have received no perceived benefit from those lenses with AF motors. Reading the article that Andy linked to, the author appears to agree with you, that the right place for the motor is in the lens, though he does not give any supporting evidence for that. In that case, why did Minolta choose to put it in the body in 1985? New lenses were going to be required anyway to benefit from AF. As they changed the mount as well, legacy MF lenses would not fit, either. For me, the in-body motor is a godsend, as I have many A-mount legacy lenses with interesting characteristics - for instance the fabled Minolta 'Beercan' and a Sigma 75-200mm f:2.8-3.5 that holds f:2.8 up to 140mm, ideal for portraits at 60% of the weight of a full f:2.8 to 200mm. Also the sharpest lens I have ever come across, way sharper than the Sigma 105mm macro used by AP for comparison tests, my Sigma 70mm macro is body-driven. The cynic in me says that the move to in-lens AF was driven as much by the industry's need to sell more kit as it was to provide a universal benefit to the average photographer. The piezoelectric ring motor has definitely simplified lens assembly, just like mirrorless simplified camera assembly. However, the price still went up! I guess it's no longer a case of " Yer pays yer money, and makes yer choice..." because the manufacturers have decided for you - it shall be mirrorless and in-lens focusing. |
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Post by nickr on Jan 15, 2023 11:44:48 GMT
This is all a bit "what have the Romans ever done for us", isn't it? "Yes, but apart from appropriate motors tailored to individual lenses, AF speed with superteles, potentially silent AF, better focus pulling in video, more efficient power usage, less to go wrong with the camera, what advantages to in-lens motors have?"  |
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Post by squeamishossifrage on Jan 15, 2023 12:38:49 GMT
This is all a bit "what have the Romans ever done for us", isn't it? "Yes, but apart from appropriate motors tailored to individual lenses, AF speed with superteles, potentially silent AF, better focus pulling in video, more efficient power usage, less to go wrong with the camera, what advantages to in-lens motors have?" There is actually nothing in your list that couldn't be done with an in-body SRM (switched reluctance motor), good software, and a unique serial number in each lens accessible to the camera - except focus pulling, as I don't understand how changing the motor location would impact that. The software would control the output characteristics of the motor to provide the customization required for each lens - if the industry had decided to go that way. |
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Post by geoffr on Jan 15, 2023 12:48:54 GMT
I can understand why the motor would have been in the body in 1985. I suggest the reason was that in 1983 there was no small motor available, with sufficient torque, to fit in a lens. The larger motor was more easily accommodated in the camera body so that was where it went. Two years later there was such a motor available and Canon chose to use it, it was a risk because its reliability wasn't known, the more conservative Nikon didn't take the risk but did incorporate the technology to adopt in lens motors later. Hence Minolta and Nikon started with in body motors and Canon took a gamble on in lens motors.
History shows that Canon was right, Nikon recognised the fact and started moving to lenses with motors, Minolta fell foul of Honeywell patents. Canon's gamble paid off as did Nikon's foresight in including the electronics for in-lens motors in its cameras together with a motor.
Why Minolta didn't, apparently, foresee the possibility of a new motor technology when it adopted a new lens mount I couldn't say, for all I know they may have done so but never having owned a Minolta camera I don't know.
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Post by geoffr on Jan 15, 2023 13:18:53 GMT
This is all a bit "what have the Romans ever done for us", isn't it? "Yes, but apart from appropriate motors tailored to individual lenses, AF speed with superteles, potentially silent AF, better focus pulling in video, more efficient power usage, less to go wrong with the camera, what advantages to in-lens motors have?" There is actually nothing in your list that couldn't be done with an in-body SRM (switched reluctance motor), good software, and a unique serial number in each lens accessible to the camera - except focus pulling, as I don't understand how changing the motor location would impact that. The software would control the output characteristics of the motor to provide the customization required for each lens - if the industry had decided to go that way. Cameras can determine the lens fitted and apply various corrections as required. It doesn't need a serial number, the part number is sufficient.
Actually, Nick has missed something important; once digital took over from film there was always the possibility that the SLR would wither. Mirrorless was probably seen early in the 21st century as the way forward. Lenses with motors were then, fairly obviously, required because of the need to interface SLR lenses with mirrorless bodies.
It would have been recognised early on that a mirrorless camera would have a shorter flange to sensor distance and thus a larger throat. The complexity of adapting an in-body motor to drive, via an adaptor, a legacy lens with a smaller throat would have been seen as unwelcome and expensive. Yes, it could have been done but, why when wires can be used more easily and don't require skilled assembly?
I accept that in many respects the advantages of in-lens motors are minimal for the user but for the manufacturer the removal of a drive shaft from a lens design offers many benefits in both manufacture and reliability. Fitting a drive shaft in a prime lens is probably not a serious issue but it must be "fun" to accommodate it in a zoom.
Clearly, what we are seeing is the result of 30+ years of crystal ball gazing by the industry. Starting with Minota, Canon, Nikon and Pentax AF experiments in the early 1980s and culminating, for now, in mirrorless cameras with capabilities to rival dedicated movie cameras.
For what it is worth, Nikon retained an in-camera motor in top of the range DSLRs right up to the end with the D6. Some lenses were never upgraded with built in motors, and now probably won't be, the 105 f2 AF DC and the 135 AF DC* specifically.
*DC Defocus image control.
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Post by squeamishossifrage on Jan 15, 2023 14:13:05 GMT
Cameras can determine the lens fitted and apply various corrections as required. It doesn't need a serial number, the part number is sufficient.
I suggested the serial number because I have found occasional differences between lenses of the same model due mainly to mechanical tolerances. The motor/software would establish what that particular characteristic was. Actually, Nick has missed something important; once digital took over from film there was always the possibility that the SLR would wither. Mirrorless was probably seen early in the 21st century as the way forward. Lenses with motors were then, fairly obviously, required because of the need to interface SLR lenses with mirrorless bodies.
I am sure the simplicity of assembly of early 'point & shoot' digital cameras helped point the way forward, as you say, and Sony took a half-step with their translucent mirror cameras. It would have been recognised early on that a mirrorless camera would have a shorter flange to sensor distance and thus a larger throat. The complexity of adapting an in-body motor to drive, via an adaptor, a legacy lens with a smaller throat would have been seen as unwelcome and expensive. Yes, it could have been done but, why when wires can be used more easily and don't require skilled assembly? That was the point I was trying to make in my 'Cynical? Moi?' bit!  I accept that in many respects the advantages of in-lens motors are minimal for the user but for the manufacturer the removal of a drive shaft from a lens design offers many benefits in both manufacture and reliability. Fitting a drive shaft in a prime lens is probably not a serious issue but it must be "fun" to accommodate it in a zoom.
Having taken apart several zooms, and then reassembled them - it's a nightmare if you only have two hands! There was one benefit, however - it kept the zoom cell close to the camera body in the design stage, and I hate having the zoom ring at the far end of the body. Clearly, what we are seeing is the result of 30+ years of crystal ball gazing by the industry. Starting with Minota, Canon, Nikon and Pentax AF experiments in the early 1980s and culminating, for now, in mirrorless cameras with capabilities to rival dedicated movie cameras.
The next step will be plasma membrane lenses grown in the lab, whereby the application of a voltage to the lens will change its shape in order to obtain focus. It's not an original idea, you know.  For what it is worth, Nikon retained an in-camera motor in top of the range DSLRs right up to the end with the D6. Some lenses were never upgraded with built in motors, and now probably won't be, the 105 f2 AF DC and the 135 AF DC* specifically. *DC Defocus image control.
...and Sony are still providing adapters for both motor-less and motored legacy lenses! |
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Post by geoffr on Jan 15, 2023 21:35:25 GMT
No problem if the motor is in the adaptor, if it were in the body it would be mechanically complex.
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Post by zou on Jan 15, 2023 22:06:54 GMT
And there was me thinking that for 95% of what I shoot autofocus is unnecessary, I'd rather have a decent distance scale on the lens. For the other 5% though, in-lens motor please.
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Post by adriansadlier on Jan 15, 2023 23:47:17 GMT
For me, the major issue is moving from DSLR to Mirrorless.
I am a Nikon shooter (Nikon D810 and Zfc bodies) and have invested heavily in Nikon Auto Focus (AF) F series glass over the years (14-24mm f/2,8, 24-70mm f/2.8, 70-200mm f/2.8,50mm f/1.4, 105mm f/1.4, 200-500mm f/5.6, all with in-lens motors).
All of them will work with a Z series camera (I have an FTZ II on order - eventually I will get a Z9 or more likely a Z8 when it is launched). They will all work as auto focus lenses.
I only have 1 screw driven AF lense, which will be manual focus only on the Z mirrorless cameras (a 105mm D series f/2.8 macro lense), and I often shoot that in manual focus anyway. The remainder of lenses I have are manual focus, older or cheaper F series lenses.
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