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Author Topic: You can't do That with medium format  (Read 120371 times)

BrendanStewart

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Re: You can't do That with medium format
« Reply #340 on: November 04, 2010, 04:10:29 pm »

Am I the only one who is utterly thrilled at the prospect of seeing what Ray can do to Ankor Wat with on camera flash?

Nick-T

Nope :)
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hjulenissen

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Re: You can't do That with medium format
« Reply #341 on: November 04, 2010, 04:30:22 pm »

Sorry for interupting, but I cant follow you on this flash stuff.

Are we down to the main benefit of MF over smaller sensor sizes is the ability of fast flash sync??

-h
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hjulenissen

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Re: You can't do That with medium format
« Reply #342 on: November 04, 2010, 05:30:02 pm »

I found Mr Rockwell quite illuminating on this topic.

http://www.kenrockwell.com/tech/syncspeed.htm

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Dick Roadnight

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Re: You can't do That with medium format
« Reply #343 on: November 05, 2010, 11:05:04 am »

Sorry for interupting, but I cant follow you on this flash stuff.

Are we down to the main benefit of MF over smaller sensor sizes is the ability of fast flash sync??

-h
No. that is one of the advantages of leaf shutters, which are fitted to good MF cameras.

It seem to be lost on most people now, but the other advantage of leaf shutters is the lake of distortion of fast moving subjects.
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hjulenissen

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Re: You can't do That with medium format
« Reply #344 on: November 05, 2010, 12:18:41 pm »

No. that is one of the advantages of leaf shutters, which are fitted to good MF cameras.

It seem to be lost on most people now, but the other advantage of leaf shutters is the lake of distortion of fast moving subjects.
But MF is used primarily for studio and landscapes, is it not? I would guess that fast moving subjects are more interesting to Canikon sports photographers?

I guess that a leaf shutter cannot be infinitely fast, just like the shutter of my 7D. What is the artifact caused by the leaf shutters "shutter time"? I would guess diffraction similar to a very small aperture?

-h
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Dennis Carbo

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Re: You can't do That with medium format
« Reply #345 on: November 05, 2010, 12:41:23 pm »

But MF is used primarily for studio and landscapes, is it not? I would guess that fast moving subjects are more interesting to Canikon sports photographers?

I guess that a leaf shutter cannot be infinitely fast, just like the shutter of my 7D. What is the artifact caused by the leaf shutters "shutter time"? I would guess diffraction similar to a very small aperture?

-h

I use MF and never have used it in a studio or for landscapes - it all depends on the subject matter and personal preference - obviously sports shooters would use a DSLR for fast frame rates, Hi ISO performance and light weight manuverability.  A MFDB at ISO 50 shooting 1 frame every 1 or 2 sec would be a poor choice. However what they are referring to is the FLASH SYNC speed not top shutter speed.  For instance my Rollei with a PQS lens can flash sync up to 1/1000, my Nikon only 1/250
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hjulenissen

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Re: You can't do That with medium format
« Reply #346 on: November 05, 2010, 02:14:52 pm »

I use MF and never have used it in a studio or for landscapes - it all depends on the subject matter and personal preference - obviously sports shooters would use a DSLR for fast frame rates, Hi ISO performance and light weight manuverability.  A MFDB at ISO 50 shooting 1 frame every 1 or 2 sec would be a poor choice. However what they are referring to is the FLASH SYNC speed not top shutter speed.  For instance my Rollei with a PQS lens can flash sync up to 1/1000, my Nikon only 1/250
If I understood Dick correctly, Leaf shutters have 2 advantages:
1) Possibility of fast flash sync, for increasing the flash-to-ambient light ratio
2) Different mechanics of shutter, leading to less/no distortion when capturing high speed movement (independent of flash)

My point about sports photography was in reference to point 2: fast movement, less distorted images.

What kinds of subjects do you work with that benefit from a leaf shutter, and is it because of pt 1 or 2 above?

-h
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UlfKrentz

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Re: You can't do That with medium format
« Reply #347 on: November 05, 2010, 02:53:06 pm »

If I understood Dick correctly, Leaf shutters have 2 advantages:
1) Possibility of fast flash sync, for increasing the flash-to-ambient light ratio
2) Different mechanics of shutter, leading to less/no distortion when capturing high speed movement (independent of flash)

My point about sports photography was in reference to point 2: fast movement, less distorted images.

What kinds of subjects do you work with that benefit from a leaf shutter, and is it because of pt 1 or 2 above?

-h

Pt 1 is the most important for us. To make pt 2 more clear: Using a focal plane shutter with short times is exposing the sensor (or film)
beginning at one side moving to the other side. This means one half is exposed after the other, this can for example result in a rotating straight propeller looking bend in the image. This won´t happen with a leaf shutter, as a leaf shutter alway exposes the whole sensor the entire time it is opened. There might be a very similar effect though, if the sensor read out is starting from one side to the other (you can easily see this with video cams, kind of funny to watch, a nightmare if you have to do a proper job with it)

Cheers, Ulf

Doug Peterson

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Re: You can't do That with medium format
« Reply #348 on: November 05, 2010, 03:24:15 pm »

But MF is used primarily for studio and landscapes, is it not? I would guess that fast moving subjects are more interesting to Canikon sports photographers?

I guess that a leaf shutter cannot be infinitely fast, just like the shutter of my 7D. What is the artifact caused by the leaf shutters "shutter time"? I would guess diffraction similar to a very small aperture?

It's not infinitely fast. One drawback of leaf shutter lenses is that they can only open and close at a certain speed. With a Hassy H that is 1/800th (depending on aperture), with a Phase One DF it is 1/800 with an internal electronic timing technology to allow an effective 1/1600th. With an RZ it is 1/400th etc etc.

The fastest that most Full Frame SLRs can transit the image is around 1/125th - 1/160th. To sync with a flash it's necessary that for some moment in time the entire frame be open (no shutter obscuring it) because the moment the flash fires any shutter in the way it shows up as a black section of the frame.

The "trick" that you are probably not thinking/realizing is that focal plane shutters can get to a faster "effective shutter speed" by using two shutters that form a slit. For instance a focal plane shutter can give you an effective 1/1000th of a second exposure by creating a slit that is about 1/6th the height of the frame. At no point in time is entire frame is being exposed. Actually the duration of shutter movement lasts around 1/125th - 1/160th of a second but any given section of the frame is only exposed for 1/1000th of a second so the ability to freeze action is equivalent to 1/1000th with the caveat of ultra fast moving objects (and then only for those traveling other-than-opposite-the-direction-of-the-shutter). The compromise is that since there is no point in time where the entire frame is being exposed you cannot fire a flash and have it expose the entire scene - only the area that the slit happens to be in when the flash fires.

So while focal plane shutter systems can go to a higher max speed they can only sync at a relatively slow speed. While leaf shutter lenses can sync at any speed they can go, they can only up to a relatively slow max speed. There is no free lunch. A select few systems like the Phase One DF and Leica S2 (assuming Leica makes good on releasing their here-to-fore unavailable LS lenses) have both a body shutter (allowing fast max speed) and a leaf shutter (allowing fast flash sync).

Also as to the comment about MFD only being for landscape and studio. That's simply factually incorrect, but markets vary widely across the world so I can see where you could get that impression. I manage the rentals out of our Miami office and we have four digital backs out on rental this week - all to fashion shooters and only one in a studio and that's a pretty typical week (during the Miami fashion season - winter). If you've never used a system with leaf shutter lenses in conjunction with strobes outdoors it's hard to understand how much more control they give you over your lighting.

Also, just in case you run across it and find it confusing - some systems like Canon and Nikon have dedicated flash systems (the SB### for nikon and the e.g. 580EX from Canon) which can "sync" at higher shutter speeds. It is a very useful tool, but it is not magic (no free lunches!) and has a major limitation. They achieve "sync" with very fast shutter speeds by changing from standard flash (where the flash fires once) to a pulsing flash method where the light pulses very very very fast (thousands of times per second) and therefore fires at least once for each section of the frame as the slit of the shutter travels across the frame. It's really cool actually, but by definition it greatly reduces the maximum power the flash can produce (since it is now trying to pulse rather than simply fire once).

So if you want to sync at f/5.6 at 1/1600th of a second at ISO50 (under exposing the sky/far-background by two stops on a sunny day) and then add flash to light up a full-length shot of a model standing 10 feet away you'll be able to do it with a single strobe head even if you put a modifier on it (soft-box/beauty dish etc) and a power pack using a MFD with a leaf shutter lens, but to do the same thing with a dSLR you'd need either many (many) SB800s in fast-sync-mode (pulsing light).

Doug Peterson (e-mail Me)
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« Last Edit: November 05, 2010, 03:43:16 pm by dougpetersonci »
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Ray

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Re: You can't do That with medium format
« Reply #349 on: November 05, 2010, 06:32:44 pm »


The fastest that most Full Frame SLRs can transit the image is around 1/125th - 1/160th. To sync with a flash it's necessary that for some moment in time the entire frame be open (no shutter obscuring it) because the moment the flash fires any shutter in the way it shows up as a black section of the frame.


I believe those figures are a little out-of-date, Doug. I don't recall any maximum flash sync in my Canon DSLRs of less than 1/250th (maybe 1/200th), and as I've mentioned, my D700 can sync at 1/320th in 'auto FP sync mode'. I presume this means that modern FP shutter curtains can move so fast that the entire sensor can be fully exposed during a 1/320th setting to allow sufficient time for synchronisation with a flash burst of about 1/1000th of a sec.

Here's an explanation from the following website http://nikonclspracticalguide.blogspot.com/2008/03/10-auto-fp-high-speed-sync-explained.html

Quote
A focal plane shutter is actually two precisely timed curtains positioned between the lens and the sensor that can either block light from hitting the sensor or allow light to hit the sensor. The reason there are two shutter curtains is to be able to get much higher effective shutter speeds.

It is important to understand is that these curtains open and close in exactly the same amount of time. So the the shutter speed is set by timing between the start of the first curtain opening and the start of the second curtain closing.

Notice that the entire sensor will be open to the light at every shutter speed up to the speed of the curtain movement itself. This is the maximum normal Flash Sync Speed.

As I mentioned, a focal plane shutter mechanism moves the curtains at a very precise speed. This speed is determined during manufacturing of the mechanism and is governed mostly by how recently the shutter was designed. In older 35mm cameras, this speed was 1/60th second, but with time, shutters got faster and faster, and in the new D300 this speed is 1/320th sec. And those race car wheels lean much further forward with an older 1/60th shutter than with the D300 1/320th shutter.
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Doug Peterson

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Re: You can't do That with medium format
« Reply #350 on: November 05, 2010, 07:20:16 pm »

I believe those figures are a little out-of-date, Doug. I don't recall any maximum flash sync in my Canon DSLRs of less than 1/250th (maybe 1/200th), and as I've mentioned, my D700 can sync at 1/320th in 'auto FP sync mode'. I presume this means that modern FP shutter curtains can move so fast that the entire sensor can be fully exposed during a 1/320th setting to allow sufficient time for synchronisation with a flash burst of about 1/1000th of a sec.

Here's an explanation from the following website http://nikonclspracticalguide.blogspot.com/2008/03/10-auto-fp-high-speed-sync-explained.html

Indeed I Probably should have said 1/125th-1/250th. However, don't let the stated specs confuse you: sync with Canon/Nikon's proprietary strobe units is often faster than can be achieved with studio strobes. They are based on some very specifically tailoring the flash to the shutter. So the 1/200th spec of a 5DII may or may not what you're able to achieve with e.g. a Profoto power pack.

There are hacks to squeeze every last quarter stop of sync speed out of your particular system (body + strobe + sync device) - canon/nikon forums are full of them, which is proof to me that those users would love the fast (full power) flash sync flexibility of a leaf shutter lens. It's odd to me that neither Canon/Nikon, nor Olympus/Sony/Pentax etc have (AFAIK) worked at all on leaf shutter lenses on their SLRs - it could be a real competitive advantage. Maybe they are banking on sensor-based technology 2-3 bodies down the line (only my guess - could happen tomorrow) that would allow the sensor to "blink" on and off at whatever virtual shutter speed one wanted. I'm venturing into territory here that I am not an expert on, maybe one of the true deep-science nerds would care to contribute.

It's kinda nice not to have to worry about such hacks, tweaks, and such. A leaf shutter lens "just works"

vandevanterSH

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Re: You can't do That with medium format
« Reply #351 on: November 05, 2010, 07:35:58 pm »

A select few systems like the Phase One DF and Leica S2 (assuming Leica makes good on releasing their here-to-fore unavailable LS lenses) have both a body shutter (allowing fast max speed) and a leaf shutter (allowing fast flash sync).
*********
And my 6 year old 203 fe with film and digital backs.

Steve
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Doug Peterson

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Re: You can't do That with medium format
« Reply #352 on: November 05, 2010, 07:37:11 pm »

A select few systems like the Phase One DF and Leica S2 (assuming Leica makes good on releasing their here-to-fore unavailable LS lenses) have both a body shutter (allowing fast max speed) and a leaf shutter (allowing fast flash sync).
*********
And my 6 year old 203 fe with film and digital backs.

True! A great system with many passionate followers!

Dustbak

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Re: You can't do That with medium format
« Reply #353 on: November 06, 2010, 03:54:34 am »

BTW. My F5 as well as my D1x used to have a 1/500th sync speed. Apparently it is possible to produce for the 35mm manufacturers. A pity Nikon dropped the faster sync speed with the D2x.

As doug mentions, which I did as well posts before, don't expect your Nikon to sync at 1/320th with anything other than the designated speedlight. I often get no more than 1/180th with the D700 when using power packs or monoblocks.
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perjorgen

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Re: You can't do That with medium format
« Reply #354 on: November 06, 2010, 02:11:15 pm »

BTW. My F5 as well as my D1x used to have a 1/500th sync speed. Apparently it is possible to produce for the 35mm manufacturers. A pity Nikon dropped the faster sync speed with the D2x.

As doug mentions, which I did as well posts before, don't expect your Nikon to sync at 1/320th with anything other than the designated speedlight. I often get no more than 1/180th with the D700 when using power packs or monoblocks.
I don't think they dropped it they are just clearer now of what it is
http://support.nikonusa.com/app/answers/detail/a_id/9631/~/f5-1%2F300-sec.-flash-sync-speed
Quote
Q: On the F5, can 1/300 sec. flash sync be used with studio strobe?
A: 1/300 sec. is only available with Nikon TTL speedlights. 1/250 is the shortest possible speed with non-Nikon flash units or studio flash

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