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Author Topic: About the Phase One / Hasselblad focusing  (Read 24525 times)

jduncan

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Re: About the Phase One / Hasselblad focusing
« Reply #40 on: November 19, 2012, 06:54:09 am »

Not really interested in responding to Anders's provocation, but I'll respond to the questions with all those question marks;) in the interest of other readers


First of all I do not need to do a google search to know that the DF only has 3 focus points. I owned both the Phase One DF645 and the Phase One AF645.
Both have the same focus point layout. No indication is given as to which focus point locks focus, but you can manually choose the one you want to use.

Regarding 35mm DSLR cameras when you have 64 or 104 focus points you have a much higher chance of a focus point being on the eyes or face.

Like here where i was shooting for 5x4 aspect ratio.





There are times where the eye will not fall behind a focus point, but in that case there will be one close by. Thanks to it being close by there will be less focus error
when recomposing. Also if the photographer is composing with the face quite far away from the center of the frame there is the option of using live view focus.
With live view focus the focusing point can be moved to any point on the screen and quite quickly with the joy stick. Some cameras even have face detection or feature detection.

With the D800 feature detection AF works like this.

First in non live view mode:
 You set the AF mode to 3D focus. In this setup the focusing system uses a single focus point
as a target. Start by pointing the chosen focus point closest to where you will be placing the feature to focus on. Then if you change the composition
the system will choose the cameras focusing point that is closest to the remembered feature. The area where focus adjustments are made is limited to the
total area of the focus points. When you go beyond that area the focus stops at where the last available focus point left off.

Second in live view mode:
 In live view mode there are two tracking options. Face detect and feature tracking. Both work in a similar way, but face detection is
based on automatic face detection (camera "knows" what faces look like) and feature detection requires a snapshot (needs to be told what to look for).
With face detection it looks for for a face in the frame and targets it for focus and will follow the face around the frame doing it's best to keep it in focus.
It is actually really quite fast, but not as fast as phase detection.
With feature detection you switch to target focus. You get a square to start with and press the center button of the multi function control on either the
body or vertical grip. This tells the camera what to look for and the camera will follow this feature around the frame and even if the photographer or subject move forwards or backwards. The feature can change size and still be followed accurately.

Here is a video that shows the live view focus tracking.

http://youtu.be/JzIxNOBPaaM

Here are a few quick tests to show how well the different focus options on the d800 work in situations where with a single
focus point you would have to recompose.

The first one is regular viewfinder focusing, but instead of using the center most focusing point I used the one closest
to the top right corner and then recomposed putting the subject right up in the right hand corner. Focus is on the ledge
under the numbers. 100% crop





The following shot is using live view focusing using using a manual set focusing point with the joystick/multifuction button
with the subject in the top right hand corner. 100% crop




The following was shot using live view target mode. First the target is set using the multi function button.
Then I recomposed and the live view focusing tracks the subject. I moved the subject around the frame
and had the tracking follow. I then chose the composition with the subject in the top right corner of the frame.
Stopped for a fraction of a second and shot the frame. 100% crop




The following photo was taken with the face recognition live view method. In doing this test I moved around so as to somewhat simulate a model
making changes to a pose. I even did some figure of 8s with the camera to challenge the live view focusing. I also move forward an backwards.
The final composition was again with the subject in the top right of the frame. What is very nice about the facial recognition focusing is that
the size of the focusing box scales continuously with size of the face hence producing accurate focus. 50% crop to keep some text in the shot.



One other really neat feature of face recognition with the D800 is face review after shooting.
Regardless of what focusing method was used when reviewing a photo you can quickly look at a closeup
of each face. This is really handy if you are shooting groups on location.
It is also really useful if you are shooting two models in one shot with a tilt shift lens wide open and one model close
and one model furthur away. Like in this shot:


Shot on film, just using it to describe the setup.
Top is without tilt bottom is with tilt.

Here is how after the fact face recognition works when reviewing images.

http://youtu.be/yNajUFMpISs

This is also useful when reviewing a fashion accessory shot. I did a shot where I wanted an accessory to be in focus as well as the face, but shoot wide
open for shallow depth of field and an 85mm tilt shift to focus face and purse. I would review the shot zooming in on the purse and then with no hunting around just one click of the front dial. It would find and zoom in on the face. This also works on HDMI output. Very handy for quick review on portable HDMI monitors.  

In conclusion. While there are some gradual improvements in AF and focus review with medium format cameras many issues remain to be addressed.  
This is particularly relevant if one keeps in mind that one of the repeated marketing points of Medium Format is shallow depth of field.
Hasselblad with true focus has at leased addressed the recompose issue with shorter focal lengths.


Thanks for taking the time to illustrate the point. This kind of answers really set the forum apart.
We can sustain a constructive discussion.

Best regards,

James
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FredBGG

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Re: About the Phase One / Hasselblad focusing
« Reply #41 on: November 19, 2012, 12:46:58 pm »

Thanks James.... your very welcome.

With MF it is important to know what benefits one gets, but it is also very important to keep in mind what one does not get.
Focusing is IMO a crucial area because MF and 35mm DSLR cameras have crammed extraordinary quality and resolution into
small cameras with small viewfinder. While the print size that can be done with these cameras has increased dramatically the viewfinders are pretty much the same.
In some cases they have lost some options. The Phase On DF+ does not have a high magnification waist level finder for example.
Also worth repeating that the focus and recompose issue is less of a problem with longer focal lengths. Being further away but still cropping tight
the angle change when recomposing is much less, however great care must be taken to avoid the model or photographer moving loser of further away during the re composition.
I'd also like to add that while the DF and DF+ have AF limitations a Mamiya/Phase one user can get a Mamiya RZ and the 150mm 3.5 as an extension to their system
and then use a high magnification loup  and manually focus on the focusing screen. Hoever Phase Mamiya needs to step up and make a waistlevel finder and high magnification loup finder
optimized for the RZ when using a digital back that is a 50% crop (or there abouts) of the RZ frame.
Another candidate as a system extension would be a Fuji gx680.
Here is Fuji's moving high magnification loup. http://youtu.be/V74h4VaQSQ4
 

Compared to film digital has also introduced another issue. With film you have a thing called focus buzz due to the thickness of film.
This means that film will have a slightly higher chance of capturing focus when shooting wide open as well as more apparent focus when you are slightly off.

In some circumstances and aspects MF cameras still have an AF focusing system and viewfinders that are more appropriate for film
having only made modest advancements while other smaller systems have made revolutionary progress in AF.

The other aspect of this is that both MF and 35mm high end Digital have reached a quality point where they both exceed most print quality
needs.See this article: http://www.circleofconfusion.ie/d800e-vs-phase-one-iq180/. For this reason functionality, ergonomics and personal preference become more important.
It is no longer necessary to make massive investments in camera bodies or bodies and backs.
This free's up resources to invest in other areas that will dramatically change ones career. There are a lot of things one can do with that extra $ 35,000.
« Last Edit: November 19, 2012, 03:17:15 pm by FredBGG »
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FredBGG

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Re: About the Phase One / Hasselblad focusing
« Reply #42 on: November 20, 2012, 01:04:04 pm »

I missed one other semi automated focusing function of the D800 that is very handy
with manual focus.
I'm not sure if this was an intended function, but it works very nicely.
I call it face detection assisted manual focus.

In live view mode you can use face detection even in manual focus mode so that when you zoom in on the LCD screen you
do not have to use the joy stick to find the face.

This is how it works. You set the camera to AF face detection and point the camera at the face.
You then switch to manual focus. The face recognition continues working. It continues working for many shots and will
recognize new "faces" too.
The advantage with this is that when you zoom in on the LCD screen the camera automatically zooms in on the face regardless of where it is in frame.
Also what is really neat is that this also works if you have more than one face in the shot.



Lets say I was shooting the shot above. In this "face detection assisted manual focus" mode
the camera would find both faces, but target the larger one. I can then zoom in with the LCD screen
and check focus. Then without zooming back out I can switch to the other face and check focus there.
This is extremely helpful when using tilt shift lenses to focus on two models faces while keeping depth of field
small. First roughly set your tilt. Focus on the close model, zoom in, fine focus, toggle to the other model and check the focus.
If it's not quite right make a small adjustment to the tilt. Check focus again and toggle back to the other face.
End result being something like this:


Again this example was shot on film, I just used it to help illustrate the method.
However keep in mind that I shot this with the Fuji gx680 with it's big 6x8cm focusing screen
and it's moving high magnification focusing loup. http://youtu.be/V74h4VaQSQ4
While phase one has a tilt shift lens it is just way to hard to use it in a situation like the above photo
due to the small viewfinder, phase one live view limitations and relatively dark and slow lens with a 5.6
maximum aperture.

Another really good use for this is if you are shooting a group of models and simply want to take a close look at each
models expression or angle of their pose. Extremely useful when using very high contrast light such as a Fresnel
where you really want each model to hold their head at the angle that is more flattering for their face.

I also discussed with Nikon implementing a manual focus assist more with two targets rather than face detection.
This would be particularly useful for using tilt shift lenses letting you toggle between the two targets when in zoomed in mode.
They were very receptive and believe that it could be implemented in firmware.

I also suggested movable guide lines for assisting composition for advertising layouts. That too can be done in firmware both in the optical viewfinder
and the LCD screen.
 
« Last Edit: November 20, 2012, 01:20:37 pm by FredBGG »
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bcooter

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Re: About the Phase One / Hasselblad focusing
« Reply #43 on: November 20, 2012, 01:33:47 pm »

It seems 35mm companies listen to the market in mass, not in specific professional needs, at least once you get past the sports photographers.

In fact I'd love to know the ratio of amateurs to professionals using higher end 35mm cameras.  I bet the numbers would be heavily titled towards amateurs.

For advertising and editorial, I've never understood why a camera like the Nikons cannot have a switch than senses when your vertical, giving you a 4:5 type crop and additionally the crop changes when you go horizontal, giving the standard 2:3 crop which fits well for double truck and web.

I'd personally  would like to see 35mm manufactures make larger optical viewing screens that can be manually focused, but that doesn't seem high on the list.

Go shoot a film Nikon F5 and then pick up a D800, D4 or any other current Nikon digital camera and you'll know what I mean.


IMO

BC

PS

I did a test for a week where I put a Nikon D4 and my Contax on a table in the studio for a week.  I set both to manual focus.

Off and on when I'd pass the cameras, I would take one, quickly manually focus on something in the studio fire one frame.  The pick up the other one and do the same.

After a week when I download the files into the computer the in focus Contax shots were about 2 to 1 to the Nikon.

Now I don't own a Hasselblad H, but I know in the brief time I've either tested or used those various H series, manual focus was easier than with my Contax, because the viewfinder is huge and bright.


« Last Edit: November 20, 2012, 01:37:40 pm by bcooter »
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Doug Peterson

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Re: About the Phase One / Hasselblad focusing
« Reply #44 on: November 20, 2012, 02:52:56 pm »

It seems 35mm companies listen to the market in mass, not in specific professional needs, at least once you get past the sports photographers.

In fact I'd love to know the ratio of amateurs to professionals using higher end 35mm cameras.  I bet the numbers would be heavily titled towards amateurs.

Biased source, but interesting marketing campaign:
http://www.petapixel.com/2012/11/20/survey-majority-of-dslr-shooters-use-their-cameras-as-point-and-shoots/#more-88681

FredBGG

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Re: About the Phase One / Hasselblad focusing
« Reply #45 on: November 20, 2012, 06:13:54 pm »

That is Sony pushing the NEX.

I'm sure that a survey of top of the line 35mm DSLR users would return totally different results.

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FredBGG

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Re: About the Phase One / Hasselblad focusing
« Reply #46 on: November 20, 2012, 06:21:58 pm »

It seems 35mm companies listen to the market in mass, not in specific professional needs, at least once you get past the sports photographers.

These companies are giants and you can rest assured that they listen to the relevant people for each of their target markets for the vastly
diverse range of cameras they make.

I have had my brain picked by various manufacturers, from cameras, lighting, film and grip gear.

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FredBGG

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Re: About the Phase One / Hasselblad focusing
« Reply #47 on: November 20, 2012, 06:42:29 pm »


For advertising and editorial, I've never understood why a camera like the Nikons cannot have a switch than senses when your vertical, giving you a 4:5 type crop and additionally the crop changes when you go horizontal, giving the standard 2:3 crop which fits well for double truck and web.


IMO

BC


Why .... does any MF have the option to automatically switch to 2:3 when going from vertical to horizontal?

At least on 35mm DSLR brand rotates it's on screen menu display when the camera is held vertically... Sony.
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FredBGG

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Re: About the Phase One / Hasselblad focusing
« Reply #48 on: November 20, 2012, 10:40:39 pm »

The  "face detection assisted manual focus"  trick I mentioned above also works
in video mode while setting up a shot. Use it as I described above and just hit record
and the lcd goes straight back to full display.
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Emilmedia

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Re: About the Phase One / Hasselblad focusing
« Reply #49 on: November 21, 2012, 08:41:49 am »

So another quesion that kinda touches the discussion here earlier:

IF i for example buy a P65+ and a Hassy body. I can not use this back on a different body? Or is it the camera that cant attach a different back then the p65+ i buy?

Doug Peterson

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Re: About the Phase One / Hasselblad focusing
« Reply #50 on: November 21, 2012, 09:26:48 am »

So another quesion that kinda touches the discussion here earlier:

IF i for example buy a P65+ and a Hassy body. I can not use this back on a different body? Or is it the camera that cant attach a different back then the p65+ i buy?

If you have a P65+ in an H-mount then you can use that back on absolutely any (working) H1, H2, or H4X. You can also use any other Phase One or Leaf H-mount digital back on your H1/H2/H4X body. It is a completely unlocked and open system in that regard.

This is not the case with the H3D/H4D/H5D.

Emilmedia

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Re: About the Phase One / Hasselblad focusing
« Reply #51 on: November 21, 2012, 09:47:41 am »

Thanks doug. So is if i for example buy a h4x or h1 to start with, and buy a second body, i'll be fine? Same goes with spare back.

Is there any adapters from H - M mount?

Doug Peterson

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Re: About the Phase One / Hasselblad focusing
« Reply #52 on: November 21, 2012, 12:34:17 pm »

So is if i for example buy a h4x or h1 to start with, and buy a second body, i'll be fine? Same goes with spare back.

Yes and yes.

Assuming of course the spare back is a Phase One or Leaf (or the Sinar H mount or CF series back). The H3D, H4D, H5D back for instance does not work on an H1/H2/H4X.

Is there any adapters from H - M mount?

No.

You can swap an H mount back for an M mount back for $3k, but you cannot adapt any given between them.

yaya

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Re: About the Phase One / Hasselblad focusing
« Reply #53 on: November 21, 2012, 12:58:26 pm »

The first thing I do when considering a camera is look through the viewfinder. If it falls short here I look no further.

Maybe it's just me but this thread which was started as a discussion about the AF on two MF systems has now turned into a 35mm user manual...yet all those poor guys reading the 35mm forums are missing out on some good advice...
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bcooter

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Re: About the Phase One / Hasselblad focusing
« Reply #54 on: November 21, 2012, 02:04:39 pm »

Maybe it's just me but this thread which was started as a discussion about the AF on two MF systems has now turned into a 35mm user manual...yet all those poor guys reading the 35mm forums are missing out on some good advice...


Yair,

At this stage I think you know there will NEVER be a question about a medium format camera without it morphing into a 35mm is better debate.

It's just a process of the internet, heck the world where words are easy, doing is hard.

I'm the first to admit I've had some issues with medium format equipment, but I'm also the first to admit that my two backs and ol' ghetto Contax cameras are the most cost effective equipment I own, (except C-stands and rollers), because they seem to last forever (the cameras and the grip equipment).

What I don't understand is why it has to be a one camera world.  Sure I could shoot everything with a 16mpx dslr and maybe no client would complain and in some instances I absolutely have to use a 16 mpx camera with fast frame rates and ultra high iso.

That said, since I do a wide variety of work, I can't imagine having a one camera fits all scenario.

So even though your comment was pretty much tounge in cheek, I think you and I both know that in todays world if you say an Aston Martin is really a rush, somebody's gonna say "yea, but you can't haul 24 Guinness cases in an Aston like you can a Transit Van.

The one thing that is always left off of these comparisons that some people really like the cameras they use, even is some tech sheet shows them inferior. 

Tech sheets don't produce photographs and can't document the experience of how we actually work.



IMO

BC
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FredBGG

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Re: About the Phase One / Hasselblad focusing
« Reply #55 on: November 21, 2012, 03:22:20 pm »

Maybe it's just me but this thread which was started as a discussion about the AF on two MF systems has now turned into a 35mm user manual...yet all those poor guys reading the 35mm forums are missing out on some good advice...

The guys reading the other forums are not missing out... I've discussed and shared this info on the Cameras, Lenses and Shooting gear.

Also your rather sarcastic comment about the thread turning into a 35mm user manual is uncalled for. I think I also covered the differences between the two MF systems.
Regarding "35mm user manual".... I am just giving an in depth description of the "state of the art" of auto focus.
Explaining how it is used is important as accuracy and usability are both relevant.
I also think that it is particularly relevant in consideration of the fact that Emil the OP
is considering a 40MP back and that the difference in image quality between a 40MP back and a D800 is very very close as this comparison shows






both are crops from this framing:



One is 35mm DSLR and one is MF digital.

(credit) http://www.photigy.com/nikon-d800e-test-review-vs-hasselblad-h4d40-35mm-against-medium-format/


« Last Edit: November 21, 2012, 03:49:38 pm by FredBGG »
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ErikKaffehr

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Re: About the Phase One / Hasselblad focusing
« Reply #56 on: November 21, 2012, 03:30:25 pm »

Hi,

Tripod and live view at actual pixels. Unless your subject is mobile, of course ;-)

Best regards
Erik


Honestly, if anyone wants to improve focus accuracy on any camera, use a good tripod with a good head.  Everything get's easier than mobility.

I start with a tripod but must admit, that under a lot of conditions move away from it, but when we review the files from any format, the ones on a tripod are more tack sharp than the ones without, regardless of lighting, movement, camera, shutter, etc.

IMO

BC
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FredBGG

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Re: About the Phase One / Hasselblad focusing
« Reply #57 on: November 21, 2012, 08:15:34 pm »

Hi,

Tripod and live view at actual pixels. Unless your subject is mobile, of course ;-)

Best regards
Erik



Actually a tripod will help focus in moving situations too, both manual and auto focus.

Even when shooting a moving model using a video tripod with a fluid head will help
auto focus by reducing jitter. By reducing jitter the AF system gets a cleaner image to work with.

IS lenses when working hand held also help the AF system in a camera.
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ErikKaffehr

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Re: About the Phase One / Hasselblad focusing
« Reply #58 on: November 22, 2012, 05:12:04 am »

Hi,

Thanks for good info.

The issue I have with live view on moving subjects is that they move. Live view manual focus does take some time. Other than that I consider LV focus to be the best method.

Best regards
Erik


Actually a tripod will help focus in moving situations too, both manual and auto focus.

Even when shooting a moving model using a video tripod with a fluid head will help
auto focus by reducing jitter. By reducing jitter the AF system gets a cleaner image to work with.

IS lenses when working hand held also help the AF system in a camera.
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