Ad
Ad
Ad
Pages: [1]   Bottom of Page
Print
Author Topic: MF vs DSLR autofocus?  (Read 1763 times)
aknicholas
Newbie
*
Offline Offline

Posts: 17


« on: November 01, 2011, 08:16:21 AM »
ReplyReply

Hi. I've been searching for a discussion of medium format vs DSLR autofocus. I shoot people and I'm interested to know what I'll experienced with a Mamiya 645 AFD iii/DM28 vs a Nikon D3x. The Nikon has 51 autofocus points, the Mamiya has 3 which I'm assuming are centered along the horizontal. The last time I owned a Mamiya there was no such thing as autofocus and I had no trouble. Now I use autofocus all the time to focus off-center. I definately want the larger sensor. So, what do shooters do when they use MF digital to photograph a model? Do you go back to manual focus?
« Last Edit: November 01, 2011, 10:03:54 AM by aknicholas » Logged

Aaron
Graham Mitchell
Sr. Member
****
Offline Offline

Posts: 2282



WWW
« Reply #1 on: November 01, 2011, 08:29:34 AM »
ReplyReply

Yes, I use manual focus. I actually picked up my first AF lens yesterday, but that was to get the 1/1000 shutter speed rather than the AF. Focus and recompose isn't going to cut it on medium format digital, if you want to shoot wide open with a 5mm depth of field. It's definitely an issue and one of the weaknesses of medium format - focus is more critical than 35mm yet we have worse AF. One solution is to focus bracket.

If you're stopping down to f5.6 or more then it should be an issue.

FWIW, the AF on the Hy6 is very good. I showed it to my rental studio here and they said "wow, a lot faster and quieter than the H4". I would just wish for an 11-point or more AF rather than single point. Why no-one will make such a sensor for the whole MF market is a mystery.
Logged

Graham Mitchell - www.graham-mitchell.com
DeeJay
Sr. Member
****
Offline Offline

Posts: 250


« Reply #2 on: November 01, 2011, 08:50:35 AM »
ReplyReply

Bit of both. Mostly manual.

If you want the speed of a dSLR don't expect to find it in MF. THe biggest issue I find is the central AF point. focus and recompose for fast fashion is tedious at best.
Logged
Brian Hirschfeld
Sr. Member
****
Offline Offline

Posts: 792



WWW
« Reply #3 on: November 01, 2011, 09:54:11 AM »
ReplyReply

Its slower then your D3x or my D3s but it is not intolerably slow. You can't really catch fast moving action....but why would you want to? thats not the point of medium format most of the time. If you want to get some action for some reason, manual with a small aperture allowing you some wiggle room with focus because of DOF would be best. The autofocus works though on medium format if you just want it for portraits, fashion etc where you want convenience, after using it for a few days you won't notice the difference. Also re-focusing after your in the general area if you recompose especially with the Mamiya works fine since it doesn't usually rack out focus while searching for the correct focus like DSLR's sometimes if you aren't able to select a focus range (like on large telephoto lenses).
Logged

www.brianhirschfeldphotography.com / www.flickr.com/brianhirschfeldphotography
---------------------------------------------------------------
Leica / Nikon / Hasselblad / Mamiya ~ Proud IQ180 owner
aknicholas
Newbie
*
Offline Offline

Posts: 17


« Reply #4 on: November 01, 2011, 10:02:43 AM »
ReplyReply

....but why would you want to?

I have my reasons Smiley

Thanks for the responses to my question, all. I've worked with manual focus before and looks like I'll need to again when I go to a larger sensor.
Logged

Aaron
Steve Hendrix
Sr. Member
****
Offline Offline

Posts: 1097


WWW
« Reply #5 on: November 01, 2011, 10:33:50 AM »
ReplyReply

I have my reasons Smiley

Thanks for the responses to my question, all. I've worked with manual focus before and looks like I'll need to again when I go to a larger sensor.


No doubt medium format auto focus is slower than 35mm - no brainer. Biggest limitation is probably moving subjects though, rather than focusing on relatively static subjects. Assuming the light is good enough, the H4, Hy6, and DF actually work ok in this regard. But moving, or focusing in lower light, their limitations come more to the fore, compared to 35mm.

Focus and re-compose works well on the H4 with True Focus and with other bodies when being conscious of the arc of movement. Yes there are 3 focus points with the Phase One/Mamiya DF, but they consist of the center circle and 2 rectangles hanging off each side of the circle, relatively clustered together. I don't find the rectangle off the circle areas useful for in-action use, because the process of switching those points (button on top menu of camera) is too tedious (well, compared to the navigational joystick of my 5D). And they're very close to the center anyway.

But I do find them useful for shooting near to subject portraits 5 feet or so distance to subject. I set the focus point to the rectangle that is on the side of the face closest to me, then the lens focuses on the near eye, rather than picking up the nose with the center circle. Generally, the center circle will pick up the closest object within that circle, and the circle is quite large compared to the small center rectangle of a DSLR. Also, again with the DF, setting custom function 19 to option 2 (accuracy, instead of option 1, which is speed) increases the consistency of the focus point.


Steve Hendrix
Logged

Steve Hendrix
Sales Manager, www.captureintegration.com (e-mail Me)
MFDB: Phase One/Leaf-Mamiya/Hasselblad/Leica/Sinar
TechCam: Alpa/Cambo/Arca Swiss/Sinar
Direct: 404.543.8475
Brian Hirschfeld
Sr. Member
****
Offline Offline

Posts: 792



WWW
« Reply #6 on: November 01, 2011, 10:36:14 AM »
ReplyReply

Sorry, I didn't want to discount the use of Mamiya with autofocus/manual focus for sports, just its more unusual and not the intended purpose. I mean what are you doing?
Logged

www.brianhirschfeldphotography.com / www.flickr.com/brianhirschfeldphotography
---------------------------------------------------------------
Leica / Nikon / Hasselblad / Mamiya ~ Proud IQ180 owner
EricWHiss
Sr. Member
****
Offline Offline

Posts: 2389



WWW
« Reply #7 on: November 01, 2011, 01:25:16 PM »
ReplyReply

Yes MF is slower but do they have Focus Trap? That's a neat thing...
Logged

Authorized Rolleiflex Dealer:
Find product information, download user manuals, or purchase online - Rolleiflex USA
BernardLanguillier
Sr. Member
****
Offline Offline

Posts: 7855



WWW
« Reply #8 on: November 01, 2011, 06:57:35 PM »
ReplyReply

The writing is on the wall. If I see the way my Nikon J1 is able to leverage face recognition to get the focus on the face every single time right in 0.3 sec with zero user operation... it doesn't take much to figure out that the next DSLR will have the same features available in live view. Once you have found the face, finding the eyes isn't much more difficult... think of the amount of photographer brain power this would free for other tasks like creative framing?

Incidently, you'll also be able to focus anywhere in the frame if that is what you want. Anybody else tired of all these dead centered catwalk images?

Considering the ease of achieving focus, the average actual image quality of 30+ mp DSLR frames will probably be significantly higher than manual focused medium format (better to have 30 tack sharp megapixels rather than 80 slightly blurred ones). Add to that much higher raw frame rates, near silent shooting in Live View mode, double memory cards for shooting safety, Wifi capability, VR, longer focals that don't break the bank/your back, much better raw processing automation with software like DxO,... it should be a no brainer for fast moving fashion images in a productive environment, right?

Cheers,
Bernard
Logged

A few images online here!
David Schneider
Newbie
*
Offline Offline

Posts: 25


Portrait Studio Owner


WWW
« Reply #9 on: November 01, 2011, 07:14:06 PM »
ReplyReply

I have a Hasselblad H3d2-39 with a Brightscreen split image rangefinder type viewfinder screen.  I press shutter down half way and it autofocuses.  If everything is lined up perfectly, I continue pressing the shutter.  If not, I then I keep shutter depressed half way and manually focus using the split image then finish pressing the shutter.  It's not True Focus, but it works well, much better than auto focus alone.
Logged
theguywitha645d
Sr. Member
****
Offline Offline

Posts: 970


« Reply #10 on: November 02, 2011, 09:44:08 AM »
ReplyReply

I don't use a Mamiya MFD, but the Pentax model. I find the AF fast and accurate and it has 7 AF points. I just did a series of portraits in the studio and the AF hit it every time. I was not taking action shots, but the subjects were not stationary either. The Pentax also allows you to fine tune the AF to particular lenses if you think the AF is consistently a little off. I don't have the feeling that the Pentax AF is any slower than a DSLR, but I also have not used the top-of-the-line models from Nikon or Canon.

On the other hand, I have found manual focus with the Pentax to be easy. The viewfinder screen is bright and large.

A downside with the Pentax might be the preview time, it is sluggish, but I just use it to get the exposure and then simply shoot. I have not found the buffer filling up and hanging up the camera.
Logged
Paul2660
Sr. Member
****
Offline Offline

Posts: 1674


WWW
« Reply #11 on: November 02, 2011, 10:02:41 AM »
ReplyReply

From my use, there is no comparison between the new Pentax 645D and the Phase One DF body (or Mamiya AFD III I think it's still the III) in regards to
AF.  The Pentax works like any other high end Canon or Nikon.  It's fast and from what I tested very very accurate.  The Phase One DF, is quite different
and may take some time to get to know.

With my DF the AF works in 3 steps, the first hit is never the most accurate, instead you get close, the 2nd press closer, the 3rd press is best it's going to get.
I also feel a modern 5.9K camera body, having only three points weighted to center is too few and out of date.  There may have been some firmware updates
to the DF body on focus in the past 12 months.  I don't have the latest firmware, but I don't own the vertical grip and thus can't apply firmware myself,
instead it requires sending the camera body to Phase One, not really up for that either.

No sugar coating, it's slow and tedious.  If you are in the studio, it may work, for landscape, it's never been an issue as my subjects aren't going anywhere
in a hurry, for action I couldn't tolerate it.  I have never tried AI servo mode and it very well might work better. 

The good news, when it finally figures out where it thinks it should be, it's generally very accurate.  Also the DF seems to handle low contrast subjects very
well, unlike my Canon AF.

Paul Caldwell
 

Logged

Paul Caldwell
Little Rock, Arkansas U.S.
Photography > http://photosofarkansas.com
Blog> http://paulcaldwellphotography.com
Pages: [1]   Top of Page
Print
Jump to:  

Ad
Ad
Ad