[Aristophanes]

I don't see how.


The claim is that a larger sensor has smaller DOF. That isn't really practically true - you can go to F/22 or F/32 or F/45. If that isn't enough (when is that?) you crop (which the chart clearly shows).

I know YOU know this but people like pictures better than they like words.

Sensors do not have DOF.

Optics do.

[Quicksand]

That's all far too complicated.

-> Falk Lumo: LumoLabs: Camera equivalence

(fortunately now cited by many independent publications, incl. on luminous landscape).

The simple story is:

Focal length f -> f' := Focal length * crop
F-Stop N -> N' := F-Stop * crop
ISO iso -> iso' := ISO * crop^2

and (f', N', iso') totally describe a photo in EVERY aspect (framing, noise, depth of field, diffraction etc.) and no dependency on the crop factor whatsoever remains.

Based on this simple piece of background knowledge, most discussions of differences of formats become useless.

All true.

But a few things are still highly correlated with crop:


(1) largest feasible effective aperture (I guess we're calling that N' here)

(2) optical viewfinder size/brightness

(3) size and weight of the camera/lens;

(4) Price!


Do (1) and (2), the benefits of which are directly correlated with larger sensors, outweigh (3) and (4), the benefits of which are inversely correlated?

That's for the consumer to decide.

[RonHendriks1966]

And I guess two stops with full frame sensor if that is true.

Thats true, but I saw an oppertunity

[Aristophanes]

While I am a huge fan of retaining the OVF, in the age of the 3" rear LCD, chimping, live view, focus peaking, etc., its singular purpose has diminished.

[falconeye]

(1) largest feasible effective aperture (I guess we're calling that N' here)
(2) optical viewfinder size/brightness
(3) size and weight of the camera/lens;
(4) Price!

I didn't want to redirect this thread's topic, so, I don't want to discuss pro vs. cons here. I just wanted to remind that sensor size can be removed from almost any discussion. What then remains (and you are hinting at that) is that available market offers do differ. Btw, size, weight and price of a lens don't typicaly differ for a given spec in terms of f',N'.

[Paul Ewins]

That isn't really practically true - you can go to F/22 or F/32 or F/45. .

Actually for the most part you can't go past f22. f32 and f45 are usually only found on macro lenses and the longer telephoto lenses. On your average variable aperture zoom it is just the long end that gets f32 or higher. If you are using primes then f22 is usually it and if it is the Nikon 50/1.4 then f16 is your minimum aperture. Have a look at the Nikon 14-24/2.8G, 24-70/2.8G and 70-200/2.8G - they are all f22 minimum aperture. It is a similar story for Canon L lenses, although at least there you do get f32 on the 70-200/2.8 and f22 on the 50/1.4.

[jogiba]

SMC Pentax 67 300mm F4 that I once had has F45 minimum aperture.

[tallgeese]

cannot believe J1 ranks 1st

[philbaum]

Any fool can make a small camera. But the point is not to compromise usability and the essence of photographic experience. ......

That camera is actually best of both worlds outcome. Not compromised at all — for those who look for a photographic tool, not a gadget.

Thank you for the recent discussion of sensor size by Falk and others. very informative.

I'm 65, and one would think i'd be conservative about my choice of camera features - but i'm not. I'll use any camera and features that let me "deliver the goods" as far as sales worthy pictures. Well last week, my brother and I took a short backpacking trip for 3 days, tent, sleeping bags, camera gear,etc.

I had very little time to pack, so in some last minute desperation, i took two cameras - my K5 with a DA 50-135 lens, and my Sony 5n with a small assortment of prime lenses.

My total pack weight was 53 lbs, which included 14.4 lbs of camera equipment. We hadn't been backpacking in years, but it was a fun experience. Except that the amount of weight both he and i carried was no fun at all. Some subjective observations:

a. The lack of a VF on my Sony 5n was the biggest drawback in using that camera. I've always liked its tilting display - but missed having a VF in harsh sunlight. (i'm going to rectify this somehow before my next trip)

b. Focus peaking is not without its drawbacks. My brother loaned me his Pentax 10-17mm fisheye and I immediately put it on my Sony 5n, thinking to get some interesting pictures with its tilting display. In the midday sun, almost all of those fisheye shots were out of focus when i got home. Assuming that the shimmering peaking lights indicated focus was my mistake, when in fact the high contrast lighting at the time was responsible for most of that "shimmering" color. If i had a VF, attachable or built-in, with my 5n, i would have had more chance of being tipped off that all was not as it should be.

On my trip, i ended up getting more keepable shots with my Pentax combination than the Sony 5n which figures - because i also used the K5 more of the time. The pretty much flat sales figures for the 2012 mirrorless cameras, IMO, reflects some disappointment with the mirrorless type of camera. I don't think the slump is permanent, but it will take more refining of the mirrorless type of cameras to bring sales numbers to a higher level.

What will bring customers customers back to continually "test drive" the mirrorless camera models, is the drive for smaller, lighter cameras. I really doubt whether i will take the K5/50-135 on my next backpacking trip because of the weight.

[kenafein]

Thank you for the recent discussion of sensor size by Falk and others. very informative.

I'm 65, and one would think i'd be conservative about my choice of camera features - but i'm not. I'll use any camera and features that let me "deliver the goods" as far as sales worthy pictures. Well last week, my brother and I took a short backpacking trip for 3 days, tent, sleeping bags, camera gear,etc.

I had very little time to pack, so in some last minute desperation, i took two cameras - my K5 with a DA 50-135 lens, and my Sony 5n with a small assortment of prime lenses.

My total pack weight was 53 lbs, which included 14.4 lbs of camera equipment. We hadn't been backpacking in years, but it was a fun experience. Except that the amount of weight both he and i carried was no fun at all. Some subjective observations:

a. The lack of a VF on my Sony 5n was the biggest drawback in using that camera. I've always liked its tilting display - but missed having a VF in harsh sunlight. (i'm going to rectify this somehow before my next trip)

b. Focus peaking is not without its drawbacks. My brother loaned me his Pentax 10-17mm fisheye and I immediately put it on my Sony 5n, thinking to get some interesting pictures with its tilting display. In the midday sun, almost all of those fisheye shots were out of focus when i got home. Assuming that the shimmering peaking lights indicated focus was my mistake, when in fact the high contrast lighting at the time was responsible for most of that "shimmering" color. If i had a VF, attachable or built-in, with my 5n, i would have had more chance of being tipped off that all was not as it should be.

On my trip, i ended up getting more keepable shots with my Pentax combination than the Sony 5n which figures - because i also used the K5 more of the time. The pretty much flat sales figures for the 2012 mirrorless cameras, IMO, reflects some disappointment with the mirrorless type of camera. I don't think the slump is permanent, but it will take more refining of the mirrorless type of cameras to bring sales numbers to a higher level.

What will bring customers customers back to continually "test drive" the mirrorless camera models, is the drive for smaller, lighter cameras. I really doubt whether i will take the K5/50-135 on my next backpacking trip because of the weight.

Go into the brightness settings and specifically set it to the bright sun setting. It's much easier to view that way in the harsh sun. Next, change your peaking color to something else, say red. The focus peaking is a marvel, once you have it setup to your liking.

[Pål Jensen]

and (f', N', iso') totally describe a photo in EVERY aspect (framing, noise, depth of field, diffraction etc.) and no dependency on the crop factor whatsoever remains.

Based on this simple piece of background knowledge, most discussions of differences of formats become useless.

What you are describing is not equivalence, it is DOF wide open equivalence and should be labeled so (in fact this equivalence isn't really a DOF equivalent either as equivalent lenses after this principle will not give the same image at the close focusing distance cross formats with real world lenses).

As others have pointed out elsewhere an image is an exposure that is defined by Aperture, shutterspeed and sensitivity of the medium (ISO). You cannot keep these constant or equivalent if you like while maintaining the same image cross formats. Nor can you change one of them without effecting at least one of the other. Hence, true equvalency across formats is practically impossible.
In fact any other constant is just as valid as reference points for equivalence; like exposure equivalence. Thats is same exposure cross formats. It is the latter equivalence that most people actually buy lenses after; eg someone having the 16-50/2.8 for the K-5 will most likely want a 24-70/2.8 for an FF camera in order to use both at their best advantage and either work around or with any DOF issues. Or they simply buy it cause it is available.

No one choose a format according to "equivalence". They choose them cause they are not equivalent. Generally larger formats yields better image quality than smaller.
In addition, no one actually shoot after the "law of equivalence". People will use their camera to their best advantage regardless of format; they will not try to equalize them in real life. Eg if you stand in front of a beautiful landscape with camera on a tripod, whether it is the Q, K-5, FF. 645 or 6X7, you'll use it at its finest ISO value to maximize quality and give a damn about equivalency. Likewise, if you want to freeze action you will do whats necessary while trying to maintain best possible image quality results. What you can say though, is that the bigger the format the bigger the chance to be forced to boost ISO in order to get the shot.

As other have pointed out; DOF wide open equivalency is the wrong math. To illustrate this is the fact that there are no 28-70/4 (FF) equivalent budget lens for the Pentax 6X7 which according to you should be in fact cheaper then the budget 28-70/4 lenses for FF ($100 perhaps?). Apart from the fact that they wouldn't be any cheaper, no one would buy such a 56-140/9.5 (or 11 or whatever) for the 67 cause people aren't interested in DOF wide open equivalency; they want exposure equivalency. Trying to market such a lens in the film days by claiming at was a kit lens equivalent to the 28-70 lenses for the 35mm format, and that you can work around its slow speed by using 3200ISO film would make people laugh.

Treating camera as a DOF (wide open) measuring device is missing the point. The camera is a tool for creative image making where photographers use whatever formats to the best of its advantage.
In addition, absolute DOF, except for having enough of it, is not a useful measure. This is because the degree of out of focusness or subject separation is highly subjective and not neccessarily highly critical in absolute values; eg. thinner DOF do not necessarily give better subject separation. And there are situation when you want subject separation but still want to show what the environment is like.

While this equivalency debate may be interesting, it is of little practical value. I feel it is a bit like posting the following statement on a sailing forum: "Circumnavigation is an impossibility provided the earth is flat". Possibly correct, but of little value to sailors.

[Uluru]

What will bring customers customers back to continually "test drive" the mirrorless camera models, is the drive for smaller, lighter cameras. I really doubt whether i will take the K5/50-135 on my next backpacking trip because of the weight.

Well, I have experienced that myself. I have never had a better holiday than when I opted for a Q + lenses instead of K DSLR + lenses. I could carry a whole Q system in my little shoulder bag, weighing only 350 grams. And I had filters and extra batteries too That's half the weight of K5 alone!

But what truly shows the value of the Q, isn't only 01 and 02 and 06 lenses — it's the 03 fisheye lens. You can't get that amount of fun with any other small sensor compact.

[monochrome]

What will bring customers customers back to continually "test drive" the mirrorless camera models, is the drive for smaller, lighter cameras. I really doubt whether i will take the K5/50-135 on my next backpacking trip because of the weight.

Our camera gear plan for vacation in two weeks at Boca Grande (we rarely use the house during prime rental season) is

Wife - Overkill

1. iPhone
2. Optio A40
3. Q + 02
4. MacBookPro

Me - Sherpa

1. Q + 01 + 02 + 06
2. Batteries
3. Charger
4. iPad

[ElJamoquio]

What you are describing is not equivalence, it is DOF wide open equivalence and should be labeled so (in fact this equivalence isn't really a DOF equivalent either as equivalent lenses after this principle will not give the same image at the close focusing distance cross formats with real world lenses).

...While this equivalency debate may be interesting, it is of little practical value. I feel it is a bit like posting the following statement on a sailing forum: "Circumnavigation is an impossibility provided the earth is flat". Possibly correct, but of little value to sailors.

I couldn't disagree more with everything you've said... it's demonstrably wrong.

For instance, please show me where DOF equivalence isn't 'wide open'...

[tclausen]

Our camera gear plan for vacation in two weeks at Boca Grande (we rarely use the house during prime rental season) is

Wife - Overkill
<snip>

Does the wife know that (1) she's considered camera gear [presumably akin to an old camera bag - not that I would call your wife an old bag, mind you, but I assume for carrying your gear when not in use] and, more importantly, (2) that you consider that bringing her along on your vacation is overkill?