[WerTicus]

Why "35mm-equivalent"? Why would I have to think to a format I'm not using?
And why do we have to talk about "35mm" on a topic dedicated to the brand new Pentax medium format DSLR?

Because I want to know what lens to get with first: given that I prefer the field of view of about 50mm on a 35mm sensor is why! :P

[Cannikin]

Why "35mm-equivalent"? Why would I have to think to a format I'm not using?
And why do we have to talk about "35mm" on a topic dedicated to the brand new Pentax medium format DSLR?

Because 35mm is a standard. Why do we need a standard? To have a benchmark against which different things can be compared, and by extension easily compared with each other, without even having to directly reference what the standard is derived from. Take the word "kilogram" for example. The "kilogram" is defined as the "mass of the International Prototype Kilogram", which is a lump of metal sitting in a vault in France. Very, very few people have ever touched or even seen this object, and yet billions of people today use this standard to compare different objects with each other without confusion or asking themselves "Why do I need to know how many International Prototype Kilograms this weighs?"

Now the standard doesn't necessarily have to be 35mm, but 35mm is a well defined (36x24mm) standard in popular use for many decades. What else would people use? APS-C? Which APS-C, film (~1.43x), Pentax/Nikon/Sony (~1.53x) or Canon (~1.6x)? How about medium format? As you can see from these threads, there is little agreement what "medium format" means.

[Uluru]

I believe we cannot even guess the market for the MF cameras, because MF is used outside the traditional photography consumer market.
If the 12,000 cameras a year is estimated size of that end consumer market (professional photography), then the industry, services, science, military and government sectors may encompass substantially larger numbers. In other words, numbers you are playing with are worthless and most likely way off the mark.

Also, your estimates on R&D and manufacturing cost, and possible profitability from presumed sales numbers, are also off the mark, because MF used in sectors mentioned above lead to contracts and deals that far exceed initial investments. It is also conceivable Ricoh will never reveal a total number of cameras ordered and produced, but only tell the number of cameras allocated for the consumer market, as other numbers are of strategic business importance.

[WerTicus]

This camera is also a halo product for Pentax from a marketing point of view.

(stupid) people will see it at the top of DXO and then go an order the K-500 instead of the D3100. ;-P

[jon404]

@aristophanes et al -- following Henry Ford's Model T price-lowering approach, what price do you think would GREATLY increase sales, and still make Ricoh a profit, taking into account lower costs from volume production? More to the point, do you think that if the price were greatly reduced... like to $3,995... would there be a huge upswing in sales? Or -- and please don't laugh -- would the price have to drop below $1000 before you can sell into a high-volume market?

EDIT -- re comment above -- (stupid) people buying a k-500 instead of a D3100? Seems like they're smart to me. And, following this high-low concept... could Ricoh make a 'low-end' K-500-type stripped-down version of the 645Z... and sell it for $2,995?

[Uluru]

This camera is also a halo product for Pentax from a marketing point of view.

(stupid) people will see it at the top of DXO and then go an order the K-500 instead of the D3100. ;-P

Exactly!

[Cannikin]

This camera is also a halo product for Pentax from a marketing point of view.

(stupid) people will see it at the top of DXO and then go an order the K-500 instead of the D3100. ;-P

Indeed, the halo effect is very real, as I have seen first hand. A number of years ago, I saw an Amazon discussion about someone wanting to buy their first DSLR. The buyer specifically was asking about the K-x, as well as the usual Canikon entry level models. Some people replied that Pentax cameras were decent, but was a "dead end system" because they have no FF.

And the person listened to them, and there was no further mention of Pentax in the discussion.

Even if the person is unlikely to get to that level (or if it even matters due to lens incompatibility), having some big top of the line model is definitely a motivator for people buying into a brand.

[RobA_Oz]

This camera is also a halo product for Pentax from a marketing point of view.

(stupid) people will see it at the top of DXO and then go an order the K-500 instead of the D3100. ;-P

Really, I think you mean "ignorant", rather than "stupid". Ignorance can be alleviated by information: stupid goes right to the bone. We take your point, though, but the difference is important. Information about Pentax is getting out in all the right places now – I see much more advertising of the products in photo magazines (including the electronic versions) by the big high street and online sellers, along with the company. Correctly handled, the 645Z will add positively to that.

[jon404]

Ditto the above comment re 'ignorant'. But, if you think about it for a moment, that K-500 is actually great value for the money. Stick an inexpensive f/2.4 35mm lens on it, and you're off to the races -- sharp images technically as good as any, anywhere. Better than a Leica, for what? $700, camera and lens? Not so bad. And, like Henry Ford's famous Model T comment, you can have any color, as long as it's black!

(re better than a Leica -- look at comparative test images on Dpreview. It's a kick.)

[falconeye]

Equivalence is a way to understand things, but its usefulness is questionable.
...
EDIT: Sometime between the time I quoted him, and the time I finished writing this response, Falconeye deleted his post.

Yes, I deleted my post because the word equivalence has become emotional for too many people.

I only wanted to help.

I found the question wether a larger format cameras has less, more, or the same issues than a smaller format camera, when being used handheld, is valid. And cannot be answered differently.

If people don't want to read "equivalence" in a post, it can't be answered at all.

Disclaimer: we are not discussing here if a more expensive, higher resolution, or heavier camera is having the same issues when used handheld. Above 3 questions are independent. A final answer needs all four answers.

[Kunzite]

So do you feel a need to know what the equivalent to my 4th geer is in your vehicle, just in case you ever buy one like mine? That way you would know in advance what gear to be in for various conditions.

Yes, because road conditions ("photographic scenes") are what you need it to handle, you know your current vehicle ("sensor/lens combination") can handle them, you need to know whether the new vehicle you're considering buying can do what your current vehicle can already handle.

Paper-testing a car, making calculations which will prove to be wrong or in the best case very much incomplete after a simple test drive; yep, sounds like "equivalence" to me

Situation 1: You do internal architectural photography. You need at least a horizontal angle of view of a little more than 90 degrees to capture an entire room from a corner. You want a better camera with low light performance and higher resolution, so you consider the 645Z. You can:

A: Know your 10mm lens on APS-C can do slightly more than 90 degrees. You know this is 15mm equivalent in 35mm. You know the 645Z's widest lens is 25mm, which is 20mm equivalent in 35mm. Thus you conclude that the 645Z will not meet your needs.

B: Order a 645Z and a 25mm from B&H, throwing down $13,500 in advance, go to the room and take a picture. You see it is not as wide as your 10mm lens on APS-C, and cannot do 90 degrees horizontal. You return it to B&H, minus the substantial shipping/insurance costs.

C. Knowing the 645Z's sensor dimensions, you can simply compute the required focal length.

[falconeye]

Why do we feel that this camera will better the DXO scores of the D800s and D600s if the 80 megapixel Phase One IQ180 sensor does not?

Most Sony sensors have a very similiar DxO score when normalized per sensor area. So, I did the math and expect the 645Z to score at 105. Maybe 3 more or less.

This assumes the 645Z to use microlenses. Which I think is highly likely, given the Kodak already did it for the 645D.

The CCDs all have very bad DxO score when normalized per sensor area. Which makes the IQ180 score relatively low.

Because 35mm is a standard.

People take offense with 35mm used as the standard when their camera isn't 35mm. I can understand that.

However, 35mm is already written into the EXIF header and used in marketing and camera menus when it comes to focal length. Therefore, there is no other obvious choice.

Except maybe scaling everything to 1m (or 10mm) sensor diagonal which would be more in line with SI, the International System of Units. But we all know how easy it is to make US Americans use SI.

Why do I keep harping on the topic? Quite simple, really. For the same reason others keep harping on the opposite viewpoint.

Again, I can understand that.

But there is something unlogical in that argument.

Once in photography, aperture was used to denote the size of the opening in the aperture blade, denoted like 10mm. To be used with, e.g., an 100mm focal length (F) lens.

People learned how to compare different F when it comes to determine exposure time: they divided F by aperture and used the quotient N (10 in the example above) to determine exposure.

At the time, it was a difficult transition, requiring the people to do some calculus in their head. And during the confusing transition, people started to write F/10 to make sure they meant a 1/10 F rather than a 10mm aperture ...

I still hear people screaming in the internet fora of the time: "aperture is aperture is aperture"

But eventually, when apertures became a fixed part of the lens, the notion F/10 became the only one in use (still different for astronomical scopes though).

Therefore, the argument that equivalent units for FStop, focal length and ISO requires math and aren't intuitive may hold true. But anybody using it really should refuse using an FStop number as well. As the same arguments apply! Life would be easier really if all cameras everywhere used equivalent units, at least optional in their menu system. That they don't (for FStop and ISO) is more due to aggressive marketing than anything else.

[Pål Jensen]

Yes, I deleted my post because the word equivalence has become emotional for too many people.

I only wanted to help.

I found the question wether a larger format cameras has less, more, or the same issues than a smaller format camera, when being used handheld, is valid. And cannot be answered differently.

It isn't very helpful cause you keep the reason why people buy a high resolution camera out of the equations and the artistic choices going into photography as well.
Equivalence notwithstanding, in real life people with MF and large format cameras are more likely to carry a tripod than people with APS bodies. And there was never a demand for 10 000 ISO 8X10 sheet film in order to make them handholdable and "equivalent" to 35mm film.
"35mm equivalency" is simply missing the point. It is also a very biased outlook....

[Cannikin]

Paper-testing a car, making calculations which will prove to be wrong or in the best case very much incomplete after a simple test drive; yep, sounds like "equivalence" to me

As I feared, caught up on an irrelevant analogy as if it somehow proves a point on this topic. Btw, in most cases you can't "test drive" systems/lenses in the conditions you need them, no more than you can go to a dealer and tell them "let me test drive all your cars on this steep, rough, backcountry road 100 miles away that I regularly go up".

C. Knowing the 645Z's sensor dimensions, you can simply compute the required focal length.

Sure, here you go: AOV = 2 arctan(d/2f). Also, please let me know a good technique to memorize what all angles of view in degrees looks like without referencing any other camera/lens.

Now the real question is, do any of you people who regularly complain about this affront to your eyes that is "equivalency" actually use multiple systems? Because I do, and no I do not have an FF camera (besides an old film one). I use both Pentax APS-C and Micro Four Thirds.

Now I didn't bother wasting any money on a m4/3 kit lens to "learn" focal lengths. One of my favorite lenses to use on Pentax APS-C is the FA 31mm f/1.8 for reasons of AOV and DOF. The first lens I bought for m4/3 was the 25mm f/1.4. Wanna know why? Because I knew that the approximate FOV and DOF of the FA 31 in 35mm terms is ~47mm f/2.7 and the 25mm f/1.4 is ~50mm f/2.8, so about the same.

I did this by memorizing two very simple numbers: 1.5 and 2. Using these two numbers, I can calculate in my head in seconds and visualize any equivalence between lenses of the two systems I do use APS-C <-> 35mm <-> M4/3. Somehow, knowing 35mm equivalence makes my life so much simpler, even though I don't use a 35mm camera. Shocking isn't it? And if Pentax ever releases an FF, well I don't need to learn any more numbers because I already did. And with the 645D/Z, I don't need to learn 645 -> APS-C and 645 -> m4/3 to understand what these lenses do, I just need to know the number 0.79 to be able to convert between any of them. It's like magic! And what if compact camera manufacturers gave their AOV in terms of 35mm in the first place (DOF is generally irrelevant for those) so I don't even need to know the crop factor for 1/2.3", 1/1.7" or 1" sensors? Well now we're getting outlandish...

Seriously though, please tell me why the hell I should go and run through complex, impossible to do in your head formulas to get AOV in degrees and DOF in terms of length, and somehow figure out a way to visualize those numbers, instead of visualizing things in terms of something I'm already familiar with (APS-C AOV and DOF) with a very simple 2 step multiplication/division process.

[Rondec]

I think if you get a 645z, you would be getting it to shoot specific things -- probably landscape work or studio work would be the main places I can think of.

Equivalence seems to focus on "wide open performance." For instance, I am sure the 645z would not have a lens to match the performance of a 35mm f1.4 lens on full frame. At least, not wide open. But, if you are planning to shoot studio or landscape it is highly unlikely that you would want to shoot at that place anyway, in which case it doesn't matter.

I truly believe that people buy lenses based on angle of view and not on ability to minimize depth of field, which is where the whole equivalence argument seems to lead. Beyond which, I am not really familiar with full frame at this point, except as it relates to APS-C and so all the comparisons don't work terribly well for me.

As far as the 645z goes, I definitely think it looks like a killer camera and if I had money for it and a couple of landscape primes, I would go for it. But I don't...