Comparison of MF lenses

[Leigh]

The XF supposedly has a vibration sensor that from what I have read, will delay the shutter (focal) until the vibrations have reached an acceptable level.

That's an interesting statement, considering the fact that it's totally impossible.

The focal-plane shutter opening is what causes the vibrations (unless your hands are shaking).

So how can you delay its opening based on vibration that has not yet occurred?

- Leigh

 

[Paul2660]

That's an interesting statement, considering the fact that it's totally impossible.

The focal-plane shutter opening is what causes the vibrations (unless your hands are shaking).

So how can you delay its opening based on vibration that has not yet occurred?

- Leigh

I don't know Leigh I don't design them just use them. You can read more about it in the Phase One marketing literature. It may be vibrations due to the mirror. Phase made quite a statement about the built in "edit" accelerometer sensor to allow the camera not to fire or fire again until all vibrations are gone.

However I also don't know anything on the timing with a LS lens. With the DF+ both shutters fire not sure on the timing.

Anything would be an improvement over the DF+ in regards to mirror shake.

Here is more detail pulled from Brian Hirschfeld's blog that covers the feature.


"The PhaseOne XF also features an accelerometer and 6-axis Gyro. Which I understand will become powerful tools as new features are added to this body through firmware upgrades. At release, an interesting feature resulting from these components is the “Seismographic mode”. This mode, uses mirror lock up (MLU) + a timer, with the aforementioned sensors to reduce vibrations when taking long exposure images. It does this by monitoring vibrations until they are reduced and then fires the camera shutter at this optimal moment. I believe this feature may only work with Leaf Shutter lenses, but I will update when this has been confirmed for me. Either way, really cool feature that takes advantage of these fancy new components, it will be exciting to see what else they will be able to do in the future (maybe tracking motion, so that a image-stabalization like de-blur feature can be used in C1?, after all once you have the movement data, its just math SEE BELOW).

Update: Seismographic mode can be used with all lenses, however it will be most effective with leaf shutter lenses, given the vibration reduction inherent in not using the focal plane shutter.

Also, we should be very excited about the possibilities of the accelerometer, at the time of my initial writing I was not aware of this, however a US Patent #US6747690 B2 entitled Digital camera with integrated accelerometers filed by PhaseOne a number of years ago suggests in its abstract that “Data relating to static and dynamic accelerations are stored with recorded image data for further processing, such as for correcting image data for roll, pitch and vibrations … Data may also be used on-the-fly for smear suppression caused by vibrations.” There are other PhaseOne patents that deal with the accelerometer, but this one would suggest that what I alluded to above could very much be on the menu in the not too distant future, and would certainly be a modern feature!"

Paul

 

[Leigh]

Hi Paul,

Well, I screwed up. I had been in a conversation about mirrorless cameras, and that mindset carried into this thread.

Certainly the mirror would be a major source of vibration.

Apologies for the error.

- Leigh

 

[jerome_m]

I suppose that the XF cameras do the following:
-close the leaf shutter
-raise the mirror and open the focal plane shutter
-wait till the vibrations have settled
-then fire the leaf shutter for exposure.

On H cameras, there is a function to keep the mirror raised and auxiliary (rear) shutter open after exposure. That allows to take a series of pictures without moving mirror or rear shutter, so without vibrations. The aperture can be adjusted in that mode, I often use it to take a series of pictures at different apertures. It can also be used to take a series of pictures at different exposures for HDR, etc...

 

[Paul2660]

Hi Paul,

Well, I screwed up. I had been in a conversation about mirrorless cameras, and that mindset carried into this thread.

Certainly the mirror would be a major source of vibration.

Apologies for the error.

- Leigh

Leigh,

No apologies needed Phase has not really placed that many of these bodies yet, so a lot is yet to be determined. I always seemed to have vibration issues with my DF body especially with the camera in the vertical. From what I have heard from others, the shutter is much softer when fired in the XF, and the mirror is dampened a bit.

I am not even sure if the accelometer feature to check for the vibrations is enabled at this time, and if it works with the IQ1, IQ2, and IQ3 backs or only the IQ3. From what I can tell, it seems the IQ2 backs will eventually get most of the "current" new features of the XF, besides the histogram display (not sure why on that) and the power share (2 more pins on the back). But as Phase adds new features, I am not sure if they will include the IQ2 backs.

Paul

 

[freaklikeme]

This is a very nice discussion and very informative. Any information about the quality of Schneider Kreuznach 120mm TS f/5.6 lens compared to mamiya 120mm f4 macro D MF lens. They advertise the tech camera image quality with this lens. Is that true?

It's true of the SK 120 since the lens is a slight redesign of the SK APO-Digitar ASPH 120 VC lens in a fancy self-contained bellows.

I haven't shot the SK at all, and have only used the older Mamiya A 120 Macro (which I still own and love), but I will say that if you have the time to put the movements to use, a PC lens or tech camera can provide a more rewarding result when close focusing than a dedicated macro, even if it weren't optically superior.

You don't have to spend $5k to get tech-camera quality out of a camera with a Mamiya 645 mount, though. You could pick up the Mamiya auto-bellows N, which gives you rise, fall, tilt and swing on the front standard with a rotating mount on the rear, and then rig up a lens board by drilling a hole in a Mamiya body cap (a little bigger than 35mm diameter for Copal 0, and I think it's 42mm for Copal 1). That may be a bit long to get to infinity with a 120, but 135 to 180 should be the sweet spot for infinity to relatively high magnification ratios, and there are plenty of excellent view camera lenses in that range that won't brake the bank. The bellows will run you between $500 and 600 new, and then it's whatever you want to spend on a lens or lenses.

 

[Leigh]

(a little bigger than 35mm diameter for Copal 0, and I think it's 42mm for Copal 1)

Proper diameers for Copal shutter mounting holes are:
#0 34.8mm
#1 41.8mm
#3 64.2mm

as given in the Copal shutter datasheets.

The actual diameter of the mounting flange is 0.2mm smaller than those values for all shutters.

There is no #2 Copal shutter.

- Leigh

 

[freaklikeme]

Proper diameers for Copal shutter mounting holes are:
#0 34.8mm
#1 41.8mm
#3 64.2mm

as given in the Copal shutter datasheets.

The actual diameter of the mounting flange is 0.2mm smaller than those values for all shutters.

There is no #2 Copal shutter.

- Leigh

Thanks for the correction, Leigh.

I didn't mention the 3 because I don't think there's enough usable area on a Mamiya body cap to support it. Also most of the lenses I've seen mounted in 3's have focal lengths that are too long for the bellows without an extension. I also should've mentioned that the Mamyia-branded caps aren't well-suited for the purpose because of the thick ridges on the edge. It's better to look on eBay for the flat generics.

 

[Leigh]

I didn't mention the 3 because I don't think there's enough usable area on a Mamiya body cap to support it.

I included the #3 just to make the table complete, in case somebody searches for such info in the future.

There are certainly LF shooters here, and probably others with lensboards large enough for the #3.

- Leigh

 

[Oamkumar]

Thanks for the replies..
Mamiya auto-bellows N is a great option I think. Its very cheap and good. I do not have to get a sinar for my kind of work.
As Doug's advice I do not think, I can use the 120mm TS lens comfortably. So I do not want to take risk.

regards,
Oamkumar