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03-18-2016, 03:59 AM - 1 Like   #76
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QuoteOriginally posted by osv Quote
that wasn't directed at you specifically.

i provided test results for the o.p. because no one was able to post photos that quantified the sensor differences for 645z vs. d810.
You still don't fully get what the OP is saying. These are images, not about quality, but about format. Because there is more to photography than empirically measurable IQ like resolution and measured DR. In any case the quality difference between the lenses used is quite large. The Samyang 14mm is actually a reasonable lens, but not in the same ballpark as the DA645 25mm.

I wanted to shoot nightscapes last night, and I knew where I wanted to do it, and what my composition was going to be. I only carried my smaller tripod with me so while the 645Z and DA 25 went on the tripod, the A7RII went on top of a reasonably flat fence pole. I wanted a long star trail - up to 2 hours in length, and I wanted the North Star in the frame. The 25mm is equivalent to 19mm on 35mm. So the Samyang is 5mm wider. That's A LOT wider.

Here are the Pentax images:

Pentax 645Z DA 25 f/4

341 seconds, f/8



5323 seconds f/13 (I was going to shoot for another 30 minutes, but temperature hit 0 C and condensation was forming and then freezing.



Here is the Sony image - I did crop a little off the bottom to make it 16:9 rather than 3:2 to get rid of the fencing in front of it.



There are several rows of stars above the limit of the Sony frame. It comes nowhere near capturing the North Star. On a tripod I could have got it in by pointing the camera further up, but that would have led to more distortion at the edges, something the Pentax image (2nd one, longer time) suffers from. If the Pentax had been 16mm equivalent, I am confident that I would have got the North Star in the frame in the first Pentax composition without raising it much if at all.

The Sony image has width I don't need, and cropping it to 4:3 won't help as I don't get more height, I just get less image. It's not always practical to move further back to get this extra width. This road has a bend behind this point, and the view changes.

There's a whole lot more to photography than charts, even in the practical rather than purely artistic sense.

The OP should definitely hold on to his D810. I wouldn't advocate having one camera as main with no decent back up. But if the format is holding him back, which he says it is, then he needs to have a different format in his armoury and as I have demonstrated, you can't always get this by stepping back and then cropping.

I'm not afraid of post processing, but like to get as much right in-camera as I can. That includes the amount of image in the frame.

03-18-2016, 04:16 PM   #77
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QuoteOriginally posted by itshimitis Quote
You still don't fully get what the OP is saying. These are images, not about quality, but about format. Because there is more to photography than empirically measurable IQ like resolution and measured DR. In any case the quality difference between the lenses used is quite large. The Samyang 14mm is actually a reasonable lens, but not in the same ballpark as the DA645 25mm.
a $300 lens, vs. a $5000 lens that's no longer in production? that's going to help the o.p. exactly how? what would you do if you needed to go wider than 25mm on the 645z?

if you wanted better or different than the samyang, the a7rii will mount any lens that's ever been made, so unlike the 645z, sony mirrorless has no lens limitations of any kind.

QuoteOriginally posted by itshimitis Quote
The Sony image has width I don't need, and cropping it to 4:3 won't help as I don't get more height, I just get less image. It's not always practical to move further back to get this extra width. This road has a bend behind this point, and the view changes.

There's a whole lot more to photography than charts, even in the practical rather than purely artistic sense.
i would have shot that scene vertically with the sony, it would have gotten everything in there that was needed... can't get much more practical than that

in this particular situation, tho, the d810 would give better p.q. for star fields than the a7rii, but i'd imagine that the 645z trumps 'em both, due to the clean iso it has.
03-18-2016, 04:19 PM   #78
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this thread has outlived it's usefulness
03-18-2016, 04:39 PM - 1 Like   #79
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QuoteOriginally posted by osv Quote
a $300 lens, vs. a $5000 lens that's no longer in production? that's going to help the o.p. exactly how? what would you do if you needed to go wider than 25mm on the 645z?

if you wanted better or different than the samyang, the a7rii will mount any lens that's ever been made, so unlike the 645z, sony mirrorless has no lens limitations of any kind.



i would have shot that scene vertically with the sony, it would have gotten everything in there that was needed... can't get much more practical than that

in this particular situation, tho, the d810 would give better p.q. for star fields than the a7rii, but i'd imagine that the 645z trumps 'em both, due to the clean iso it has.
You cherry pick what you want to bother reading. READ MY POST AGAIN I clearly say I was not comparing them on quality. I was comparing them on format.

I didn't want to shoot in portrait orientation. Why should I shoot in portrait orientation to get what I could get with a 4 x 3 format in landscape? (and vice versa). That would be a completely different composition. The 3 x 2 of most cameras in portrait orientation is one of its weakest attributes. It is too narrow that way. Shooting with an UWA doesn't make it any narrower. The frame is still too narrow.

Learn to read and comprehend rather than patronise. The OP has said that he wants to shoot natively in 4:3. The only camera that will do this apart from medium format is a Panasonic M4/3 that has 12 megapixels.

I'll take you seriously when you stop being a fanboi.


Last edited by itshimitis; 03-18-2016 at 04:46 PM.
03-18-2016, 04:49 PM   #80
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QuoteOriginally posted by itshimitis Quote
You cherry pick what you want to bother reading. READ MY POST AGAIN I clearly say I was not comparing them on quality. I was comparing them on format.

I didn't want to shoot in portrait orientation. Why should I shoot in portrait orientation to get what I could get with a 4 x 3 format in landscape? (and vice versa).
calm down, lol

you said: "The Sony image has width I don't need, and cropping it to 4:3 won't help as I don't get more height, I just get less image", and i directly addressed that concern by stating "i would have shot that scene vertically with the sony", and the frame was not too narrow in this situation.

shooting it vertically also eliminates the worst distortion, because you would have had plenty of room to crop the top and bottom of the frame.

it would have worked the same way with the d810, so this isn't a sony fanboi issue
03-18-2016, 05:00 PM   #81
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QuoteOriginally posted by itshimitis Quote
I'm not afraid of post processing, but like to get as much right in-camera as I can. That includes the amount of image in the frame.
Which is why I think we should have options with regard to medium *format*. i.e. "back in the day" we had a choice of 6x6, 6x7, 6x8, 6x9, and 6x12 medium format cameras. In fact, many of us owned more than one. So I applaud the point and wish we had a choice of square format medium format digital!!! (again)

Michael
03-18-2016, 05:04 PM - 1 Like   #82
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QuoteOriginally posted by osv Quote
calm down, lol

you said: "The Sony image has width I don't need, and cropping it to 4:3 won't help as I don't get more height, I just get less image", and i directly addressed that concern by stating "i would have shot that scene vertically with the sony", and the frame was not too narrow in this situation.

shooting it vertically also eliminates the worst distortion, because you would have had plenty of room to crop the top and bottom of the frame.

it would have worked the same way with the d810, so this isn't a sony fanboi issue
You need to understand better the difference between 3:2 and 4:3 format, and its photographic consequence, because you aren't getting it. At all.

If I want to get the image I want, I want a little less width and a little more height (or vice versa based on orientation) then with a 3 x 2 I have to move further back to make the composition looser and then crop to 4:3. Both of these impact image size and also ultimately, image quality. Sure if I want 4 x 5 then I either have to shoot with a view camera or crop. For me, 3 x 2 is the weakest of the image formats. it's too narrow. it's one of the reasons why when I had the 645D and the D800/e, I would prefer the 645D images over the Nikon, even if the Nikon was in many ways a more practical camera. I preferred the depth of the 645's frame. With the Nikon (and now with the Sony) I could only crop it to get that feeling of depth, but I would have to change my viewing point, which can affect DOF.

Why? because I preferred the look, and the format that medium format gave me. Particularly in print. Unfortunately just as 3 x 2 dominates the camera market, so it also dominates the print market, most media is in 3 x 2 (A4 for example). But at least you can just order papers in a format you want, you just have to pay more for it.

I crop many of my Sony images to 16:9 or 16:10. As you said earlier, that makes them perfect to look at on widescreen image panels. But I don't want images that are only made of pixels. Pixels have not the life of a print. By life, I mean energy, not lifespan. I want to print my best shots. If you're shooting for TV screens or laptop screens, you don't need any more than 8mp.

---------- Post added 03-18-16 at 05:11 PM ----------

QuoteOriginally posted by MJSfoto1956 Quote
Which is why I think we should have options with regard to medium *format*. i.e. "back in the day" we had a choice of 6x6, 6x7, 6x8, 6x9, and 6x12 medium format cameras. In fact, many of us owned more than one. So I applaud the point and wish we had a choice of square format medium format digital!!! (again)

Michael
I agree. The technology is there already in theory. There was a Panasonic where you could choose the format you wanted - 3:2, 4:3, 6x6 (which was a 4x 3 cropped). It would need a much larger sensor to do this on medium format.
03-18-2016, 06:11 PM   #83
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The D810 is an excellent all-around camera with great IQ, and it can do many thing well. But itshimitis has made an important point about 4:3 ratio - it is one of the main reasons that some of us choose the 645Z. This is the classic, extremely pleasing aspect ratio for fine art (go to an art show and see how many painters create in 3:2) and is an important factor for those of us selling gallery prints. When you are shooting a 3:2 ratio DLSR but desire a 4:3 ratio composition, you must compose for the short side and then crop the long sides in post, resulting in fewer pixels and less resolution to work with. This matters when your best selling print sizes are 40" x 30" and 50" x 38".

Here are a couple test photo comparisons to illustrate: the D810 and the 645Z shot by Imaging Resource on their standard test scene, both files raw, both upsized with Photoshop's excellent Preserve Detail algorithm to 30" on the short side for 40x30 printing. If you can't see the difference here or it does not matter to you, then save your cash and enjoy the greater versatility of a DSLR or mirrorless system. If the difference shown does matter to you and/or your customers/clients, then the 645Z continues to be the highest image quality available at its price level. (hint: in the image of the peppercorns note what is happening in the upper right with noise in the red color and aliasing in the lines).

Also attached is the DxO test comparison that was leaked some weeks ago.

(Note: the forum software has butchered these, so feel free to download and process yourself from Imaging Resource if you want to view without the compression and resizing)

Cheers,
Ross

Attached Images
     

Last edited by SeattleDucks; 03-19-2016 at 11:03 AM. Reason: clarity
03-18-2016, 08:25 PM   #84
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QuoteOriginally posted by itshimitis Quote
You need to understand better the difference between 3:2 and 4:3 format, and its photographic consequence, because you aren't getting it. At all.
no, you posted a specific failed scenario wherein you claimed that the a7rii wouldn't work, because it never occurred to you to use the camera in portrait mode.

the generalizations you keep making don't apply to all situations.

QuoteOriginally posted by itshimitis Quote
Both of these impact image size and also ultimately, image quality.
your exact words were: "You seem more of a gear head than a photographer. When do you see images as anything other than pixels?"

QuoteOriginally posted by itshimitis Quote
There was a Panasonic where you could choose the format you wanted - 3:2, 4:3, 6x6 (which was a 4x 3 cropped). It would need a much larger sensor to do this on medium format.
cropping the sensor is no different than cropping the image.

i will repeat again: if you can't visualize the image composition without help, put some gaffer tape on the lcd, so that it's a square picture.

sensor aspect ratios are determined by consumer demand, if cameras don't have square sensors, it's because no one wants it.

---------- Post added 03-18-16 at 08:41 PM ----------

QuoteOriginally posted by SeattleDucks Quote
Here are a couple test photo comparisons to illustrate: the D810 and the 645Z shot by Imaging Resource on their standard test scene, both files raw, both upsized with Photoshop's excellent Preserve Detail algorithm to 30" on the short side for 40x30 printing.
you posted examples at 200% viewing, so how do you figure that they are upsized for 30"? looks to me like your pics are upsized for 60", not 30".

that makes about as much sense as feeding the printer images at half-size, and letting it do the upscaling automatically.

QuoteOriginally posted by SeattleDucks Quote
Also attached is the DxO test comparison that was leaked some weeks ago, for those who live and die by specs alone.
there is no dxo rating for the 645z, the only data available is the sensorgen stuff that i already posted, and it shows very little improvement over the d810.
03-19-2016, 12:33 AM   #85
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Can't you get it into your head that a portrait orientation composition is a completely different composition to a landscape one? Also because the 3x2 is to narrow on one side, and no I'm not going to deface my camera with gaffer tape. Because you've not answered the question on so many occasions I assume that you don't print photographs you just pixel peep images on a screen. It just means that you deal with theoretical images, not photographs. You still also ignore the fact that chopping off width does not give you height. To get that height you have to mive further away from the subject which in some circumstances in portrait sessions can change DOF.

The 645z has been measured by DxO. I've seen that table before on this forum.
03-19-2016, 01:16 AM - 1 Like   #86
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How do you shoot that image in portrait on 3:2? it would not have the width. Fail OSV.
03-19-2016, 01:33 AM   #87
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Although I should probably just unsubscribe from this thread, I think we can all agree that from the OP's question, there will be many different opinions or perspectives and that the OP can decide for him or herself what makes sense to them and what is less relevant or more pertinent to their query. No one that posts should be insulted or mocked just because someone doesn't agree. If every post is something I already know and agree with, what's the point of this forum?
03-19-2016, 01:55 AM   #88
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QuoteOriginally posted by osv Quote


cropping the sensor is no different than cropping the image.

i will repeat again: if you can't visualize the image composition without help, put some gaffer tape on the lcd, so that it's a square picture.

sensor aspect ratios are determined by consumer demand, if cameras don't have square sensors, it's because no one wants it.[COLOR="Silver"]



Just to comment on this, the Panasonic I am talking of uses an oversized sensor and uses different aspect ratios within the sensor. The whole sensor is never used 100%. It starts life as a 16 or 20mp sensor but only has 12 effective mp. WYSIWYG in the viewfinder/backscreen. No need for masking tape/duct tape.

---------- Post added 03-19-16 at 02:15 AM ----------

QuoteOriginally posted by 2351HD Quote
How do you shoot that image in portrait on 3:2? it would not have the width. Fail OSV.
Indeed. This is what a 3:2 portrait would look like:



and this is that same 3:2 image cropped (as per your suggestion, OSV) to 4:3



Notice the device I am using - the road as a leading line -is still chopped? That's because I don't have the width of a 4:3 sensor. Cropping a 3:2 doesn't give me that. Yes the extra height would have got the North Star, but the composition wouldn't work as I cannot get into the position needed to get the composition I want. I can move the composition left by moving to the right to get the road but then I would lose the North star.

In simple, visual terms, the above shows you the consequence of aspect ratio. Sure you can crop the image to give the appearance of a 4:3, but when you are composing with a 3:2 all you get is a 3:2 cropped to 4:3. they aren't the same thing. At all. Period. Full stop. .

Last edited by itshimitis; 03-19-2016 at 08:43 AM.
03-19-2016, 10:47 AM   #89
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QuoteOriginally posted by itshimitis Quote

The 645z has been measured by DxO. I've seen that table before on this forum.

Indeed: Pentax 645Z Ranked Highest by DxOMark - Photo Industry News | PentaxForums.com
03-19-2016, 04:44 PM   #90
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QuoteOriginally posted by itshimitis Quote
Can't you get it into your head that a portrait orientation composition is a completely different composition to a landscape one? Also because the 3x2 is to narrow on one side, and no I'm not going to deface my camera with gaffer tape. Because you've not answered the question on so many occasions I assume that you don't print photographs you just pixel peep images on a screen. It just means that you deal with theoretical images, not photographs. You still also ignore the fact that chopping off width does not give you height. To get that height you have to mive further away from the subject which in some circumstances in portrait sessions can change DOF.
no, in the specific scenario you posted above, if the ff sensor/14mm lens is shot in portrait mode it has nearly enough vertical fov(aka width, since it's rotated) to cover the horizontal fov of the 645z/25mm lens... since you can't visualize that, do the math instead... 645z has a .79 focal length multiplier/4:3 sensor, ff is 1:1/3:2 sensor, Angular Field of View Calculator

81.2 degrees vertical(aka width, since it's rotated) for the ff sensor
82.5 degrees horizontal for the mf sensor

so it appears to me that you may or may not be short a degree of fov, depending on how accurate the actual focal length of the lens really is.

---------- Post added 03-19-16 at 05:00 PM ----------

QuoteOriginally posted by 2351HD Quote
How do you shoot that image in portrait on 3:2? it would not have the width. Fail OSV.
oh? do you see a problem with the math that i posted? the width is essentially the same, and you have much better vertical coverage to include both the road and the north star in the shot, which itshimitis could not do with the 645z/25mm combo.

shooting it with the ff camera would have been the better choice, compositionally speaking... cropping it like itshimitis just did does not work at all.

104.3 degrees horizontal(aka vertical, since it's rotated) fov with the ff sensor/14mm lens
66 degrees vertical fov with the 645z/25mm lens

Last edited by osv; 03-19-2016 at 05:26 PM.
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