Pages: 1 ... 6 7 [8]   Go Down

Author Topic: Phase One IQ250 - 11 things you need to know and Q&A  (Read 41122 times)

Primus

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 52
Re: Phase One IQ250 - 11 things you need to know and Q&A
« Reply #140 on: January 27, 2014, 04:47:16 pm »

I read this "Well, I tested my A7R on a tripod in my backyard in 'field conditions' using a 600mm Mk II Canon lens with the metabones adapter. At f4 (wide open), at 1/10s, there is NO shutter shake. Sure the image gets a bit sharper at f5.6 1/800 sec, but you would expect that."... I am not sure why use BOLD letters proclaiming absence of shutter induced shake @ 1/10s :-) whereas everybody knows that it is not the shutter speed to test for it (if you want to isolate its effects and not other efects like when you have a really bad tripod/head/whatever)... as for your testing @ faster 1/10 you indeed write = "I found nothing from 1/10 to 1/800 that would suggest shutter shock.", but that's another story, which in liew of your special accent on 1/10 exposure speed does not add any confidence in you as a tester, sorry... now reread how testing was done by Lumo and repeat (pay attention to the whole mass of camera/lens combo too - you might want to repeat it w/ FE lenses or so... I am getting way less shutter shake when I am using E-M1 with battery grip and P35-100/2.8 vs E-M1 alone with P20/1.7 and with the E-M1/P20/1.7 combo I am getting it in 1/100-1/200 shutter speed range... )

sorry, I thought it would be obvious if I said that 'sure things get sharper at 1/800' that I tested at many different speeds in between. My bad.

I also admit I am not a pro, do not make any money from photography and could hardly call myself an 'expert' of sorts and so yes, perhaps I am not the right kind of 'tester'.

However, I also find that there is way too much internet hype about this and many other issues. I do own (and have owned) expensive camera gear (the IQ180 for example) which while it does not qualify me to be an authority on anything, should at least suggest that I read a lot about photography and equipment and (hopefully) spend my money wisely.

Which is why, before investing further into the A7R lineup (I already have the Nex7 with a lot of Sony and Leica glass), I wanted to make sure with my own testing if the shutter shake is really an issue (for me) or not. So I set up a simple target in my backyard (yes, I do have Edmund Optics' resolution chart etc, but didn't want to use that, the idea being to simulate field conditions) for the test.

Yes, there are many things that can cause a blurry image at 1/10 sec with a 600mm lens on a tripod. Point is I got very sharp images all through from 1/10 to 1/800 sec. 

It does not matter to me the least if you are not convinced in any way, that was never my intention. I am happy with my results and that is all I am concerned about. Wanted to say this for the benefit of others like me who may be worried about the 'shutter shake' phenomenon, that it may not affect all copies of the camera or perhaps there is some as yet undiscovered reason  why not everyone has experienced it (and yes, I have discussed this with others who own the camera).

FWIW, I also tested (yes, the same 'crude' backyard test) my 70-200 f2.8 lens, my 24-105 f4 lens at various speeds, handheld and on tripod. No shake.

Again, I am not interested in duplicating anybody else's methodology. Just wanted to satisfy myself that my camera is alright, which it is. Now I can happily go ahead and order the 24-70 and other lenses as they become available.

Regards.
Logged

BernardLanguillier

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 13545
    • http://www.flickr.com/photos/bernardlanguillier/sets/
Re: Phase One IQ250 - 11 things you need to know and Q&A
« Reply #141 on: January 27, 2014, 06:02:30 pm »

With all due respect:
- if you see a difference between 1/800 and 1/10 sec, then you are confirming the fact that shutter vibration does have a negative effect,
- the heavier the lens, the less it is going to show so it is not surprising that the shake is limited with a 600mmf4.

Cheers,
Bernard

robdickinson

  • Full Member
  • ***
  • Offline Offline
  • Posts: 239
Re: Phase One IQ250 - 11 things you need to know and Q&A
« Reply #142 on: January 27, 2014, 06:36:55 pm »

With respect, posting 100% crops is not going to tell the whole story.

It will look almost exactly like any other exmoor CMOS sensor of similar pixel pitch. This is not surprising!

You have though twice the area and twice the pixels of a 135 format cmos sensor.

If you frame and shoot the same shot on say a D600/A7 vs an IQ250 you will have a much better print from the IQ250, it should be equivalent to about 1 stop better noise. It may have better resolution but at some point noise will kill resolution differences , so it will likely just print cleaner.

The downside here for MF is that I can buy relatively cheap f1.4 glass for 35mm and be two stops ahead of most fast MF lenses.

As a canon 35mm shooter this sounded great on the surface but as soon as you look at details (sensor size, fps, forced dark field frames, not to mention cost) it utterly falls apart as a proposition.
Logged

bjanes

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 3366
Re: Phase One IQ250 - 11 things you need to know and Q&A
« Reply #143 on: January 27, 2014, 07:08:32 pm »

With respect, posting 100% crops is not going to tell the whole story.

It will look almost exactly like any other exmoor CMOS sensor of similar pixel pitch. This is not surprising!

True. The per pixel performance is approximately equal.

You have though twice the area and twice the pixels of a 135 format cmos sensor.

If you frame and shoot the same shot on say a D600/A7 vs an IQ250 you will have a much better print from the IQ250, it should be equivalent to about 1 stop better noise. It may have better resolution but at some point noise will kill resolution differences , so it will likely just print cleaner.

Not quite. The IQ250 sensor is 44x33 mm = 1452 sq mm. The FF 135 sensor is 36x24 mm = 864 sq mm. The ratio is 1.68, not 2. Other factors being equal, this translates to a 0.74 stop difference in DR. The SNR varies with the square root of the number of photons collected.  Other things again being equal, the IQ250 would collect 1.68 times the number of electrons and the SNR would improve by a factor of 1.3. Much better print than 135? Doubtful.

Show us your prints.

Regards,

Bill
Logged

robdickinson

  • Full Member
  • ***
  • Offline Offline
  • Posts: 239
Re: Phase One IQ250 - 11 things you need to know and Q&A
« Reply #144 on: January 27, 2014, 07:13:09 pm »

I hadnt bothered to do the calculations because in reality I will never own this back..  And it works out even poorer than my guestimate.

I already stitch multiple astro shots, not entirely sure where the ID250 advantage at high ISO is ..
Logged

Doug Peterson

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 4169
    • http://www.doug-peterson.com
Re: Phase One IQ250 - 11 things you need to know and Q&A
« Reply #145 on: January 27, 2014, 07:40:06 pm »

The point is not to race to see whether MF or 35mm can take a picture in the darkest environment. 35mm will always win that battle - they have f/1.2 (or even f/0.95) lenses, lenses with 2-3 stops worth of image stabilization, and bodies which sacrifice everything for better low light performance (e.g. low resolution, only "pretty good" color).

The point is, if you're considering medium format, but know you work in diverse situations, can you confidentially pack just an IQ250 where perhaps you could not with a P45+, or IQ180. Or can you pack an IQ250 where previously you would have packed an IQ160 and a 5DIII?

Some sports cars have no trunk, other sports cars have reasonable trunk storage. This announcement is like a sports car which has the same storage as a mid-sized SUV but still behaves like a sports car. The question is not whether it has more storage than a large SUV - it does not; but it will attract attention from more buyers than a sports car that had only a very small trunk.

Primus

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 52
Re: Phase One IQ250 - 11 things you need to know and Q&A
« Reply #146 on: January 28, 2014, 09:17:38 am »

With all due respect:
- if you see a difference between 1/800 and 1/10 sec, then you are confirming the fact that shutter vibration does have a negative effect,
- the heavier the lens, the less it is going to show so it is not surprising that the shake is limited with a 600mmf4.

Cheers,
Bernard
Disagree respectfully.

I think we are causing thread drift, but nevertheless.

I tested the 600, 70-200, 24-105, which are my most commonly used lenses. I did not go wider than 24. I tested from 1/10 sec to either 1/400 for the shorter or 1/800 for the big telephoto lens, with variable speeds including 1/100, 1/250, at apertures ranging from wide open to f8. I wanted to eliminate as many variables as possible hence the tripod for all (I did test handheld too, but not extensively), shooting tethered.

I did not have a truly rigid setup for the big lens, using a P0 monoball instead of my Wimberley. I think it is a given that  a 600mm lens would produce a sharper image at f5.6 and 1/800 than at f4 and 1/10 especially on a not so rigid support.

Perhaps the big lens eliminates shutter shake (kicking a bus as opposed to kicking a car as Lloyd says), but IMHO any shake, whether originating in the camera or lens or tripod would get magnified at  longer focal lengths.

Here is a direct quote from Joseph Holmes (who claims he is one of the original three who highlighted this issue)  "This happens more with longer lenses and more with lenses where the camera itself is not mounted directly to the tripod, rather the lens is mounted via its own foot, or its mounted to the foot of an adapter, so the camera is at the end of a “branch” sticking out in space, unsupported so that it is more readily made to shake."

Regards,

Pradeep
Logged

Doug Peterson

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 4169
    • http://www.doug-peterson.com
Re: Phase One IQ250 - 11 things you need to know and Q&A
« Reply #147 on: January 29, 2014, 02:35:24 pm »

Our first demo IQ250 has arrived! Testing to commence tomorrow and Friday.
Pages: 1 ... 6 7 [8]   Go Up