Full frame cameras

[dem]

3. Diffraction: answered above. This is a function of pixel size, not sensor size, so it can't be answered without additional information.
4. DOF: answered above. yes, if you open the aperture wider on the smaller-sensor camera to compensate (assuming the aperture goes wide enough to allow one to do this).

These two points are inconsistent. To define either diffraction or out of focus blur one can use either a circle of confusion (which depends on the sensor size) or a pixel size (which does not depend on the sensor size) as the area to which the blur should be limited to produce a sharp image. Traditionally people use CoC for both diffraction and DOF. For example, Joseph James says: "The [equivalent] photos all have the same DOF (as well as diffraction softening) when they are taken from the same position with the same focal point and have the same display size." He repeats this quite a few times on his page.

Bob Atkins shows a table to demonstrate how to keep diffraction softening constant across different formats when printing 8 x 10:

http://www.bobatkins.com/photography...ffraction.html

So, if we agree to use CoC that normalises images taken with different cameras to a given output format (e.g. 8 x 10 prints), then the answer to questions 3 and 4 is YES.

If we use a pixel size as a reference and view our images at 100% magnification, then the answer to both questions in NOT NECESSARILY. Many DoF calculators allow you to switch from the traditional CoC approach (that does not take into account Mpx count) to the pixel-peeping approach (for which you need to enter the number of Mpx in your camera). Then they simply shrink CoC value to match that number of megapixels and report back a much narrower DOF for the same shooting scenario.

There is a tutorial on CiC that explains when one can detect diffraction softening as the lens is stopped down. The smaller the pixels, the sooner one can see some softening at 100% magnification. This does not mean that this softening will be detectable in 8 x 10 prints, for example.

[rpcrowe]

I don't know if I missed this but as an added advantage of the full frame camera over your T2i, is the dual dial control system. IMO, this really puts a camera over the top as opposed to the Rebel type cameras which are more menu driven. Of course, some more pro type crop sensor cameras also have the dual dial control system; these include the two digit models of crop sensor camera 30D through the 80D and the single digit crop sensor models which include both the 7D and the 7D2.
This capability will not necessarily mean better images but, will most likely mean a more pleasant experience in using these cameras.

[William W]

. . . To define either diffraction or out of focus blur one can use either a circle of confusion (which depends on the sensor size) or a pixel size (which does not depend on the sensor size) as the area to which the blur should be limited to produce a sharp image. Traditionally people use CoC for both diffraction and DOF. . .

I really liked Post #81, it made me think, (i.e. think back in time), thanks.

(continuing the theme of my last post) That's akin to what we did with film - what I mean is:

Traditionally we'd use Circle of Confusion as the base for Diffraction and Depth of Filed. CoC being dependent upon the Camera Format, aka colloquially 'Film Size'. I am pretty sure, in fact, that was what we were taught, as theory, in my Diploma Courses.

However, in the real world and considering "Equivalence", different Film Emulsions have different characteristics, additionally those characteristics, as they would appear to the Viewer's Eye in the FINAL PRINT, could be manipulated by (not limited to): Exposure (i.e. under or over); Development Time; Development Temperature; Medium on which the Print was made (simple example, different Paper Grades).

***

Personally I find the concept of “Equivalence” firstly interesting and secondly (more importantly) very useful.

I think Paul’s comments are quite harsh and (more importantly) inaccurate.

. . . totally correct in being sceptical about the concept of equivalence.

Yep, being sceptical promotes thinking and debate and more often than not learning.

It is a flawed concept initiated by some camera reviewers in an attempt to put different format cameras on an equal footing. They are not.

Yep, some camera reviewers have absolutely no idea what they are talking about and they use what they consider as their acquired knowledge to make all sorts of silly claims and statements. And obviously different Cameras Formats are not on an equal footing. But it is not accurate to state that the concept of “Equivalence“ is initiated by reviewers nor to imply that’s the only purpose of the concept.

The concept of “Equivalence” can be very useful, as one of many markers, when comparing and contrasting Camera Formats and the Lenses and Cameras which are available to use in those different formats.

As a really simple example – “Equivalence” can show us very quickly, just as my colleague Paul explained in 1980, that 135 Format Camera is still king if the Photographer is passionate for very shallow depth of field imagery.

Those who are not sufficiently knowledgeable to appreciate the concept are not helped by it's use. Those who understand what equivalence really means also understand the implications of using different formats without the need of using equivalence comparisons.

A bit harsh and also generalizing, as well as speaking for others’ opinions.

To ignore the effect on shutter speed (or ISO) when using an equivalent aperture to achieve a matching DOF prevents the equivalence concept from being of any practical relavence other than possibly in reference to studio, landscape or similar photography.

Of course we cannot dismiss Shutter Speed and ISO.

But “Equivalence” as I perceive the whole concept doesn’t ‘ignore’. At some stages in the process of the using "Equivalence" we might ‘not include’ Shutter Speed and ISO. For example the simple comment above, ““Equivalence” can show us very quickly . . . that 135 Format Camera is still king if the Photographer is passionate for very shallow depth of field imagery.”, that statement does not take into account ISO or Shutter Speed; nor does it take into account other elements which Photographers may consider to be critical for their own particular needs, e.g. any particular Lens’s sharpness when wide open; Size and weight of the Camera and Lens, etc

***

The way I think about “Equivalence” is that it is one part of the whole, and it can be very good guide for choice making.

In so far as anything being a guide for me making practical choices in the field: to get what I want in my Photography, I’ve always found it useful to limit variables of any theory that I have acquired.

For example, we can (and many forums have) debated the topic of Depth of Filed, until Mrs Brown’s cows come home – and that debate will go on for years and years.

Of course one key variable in (the final) DoF (as SEEN by the Viewer) is the PRINT/IMAGE SIZE – and another is the VIEWING DISTANCE . . . but thinking about all those variables really hurts my head when I am making pictures . . .

What I USE from the THEORY is this: With my 5D cameras at F/2.8, I will have 6 inches DoF for an Half Shot - that’s Nose to Ear, focus on Leading Eye, and if grab one of my APS-C Cameras, then I need F/1.8 to get the same.

Understanding the theory and then taking ONLY (what I consider the useful bits for me) to make Photos means that I have fewer brain aches and much more brain function to concentrate on other stuff, which is really important.

WW

[William W]

. . . there is a lot of misunderstanding among newcomers to photography about equivalence. I see many posts on other forums where folk think that an aps-c 100mm lens is a different focal length compared to a FF 100mm lens. Or they think that a aps-c sensor and lens will give greater "reach" than a FF camera and the same FL, without understanding the significance of pixel density and the "enlargement" of the smaller sensor image.

Indeed. There is a lot of misinformation on the WWW.
Misinformation leads to factoids becoming facts.
Erroneous facts lead to poor results.
Poor results leads to people getting frustrated with their Photography, when, it should have been a very happy and positive journey of fun and learning for them.

One of the benefits and a key major strength of CiC, is the time and effort that people take to make comments as to what they think will be useful and beneficial to others, especially newcomers to The Craft

I agree – with Post #80. It serves as a warning to newcomers to check the validity of comments on forums and more importantly the validity of the sources of those comments.

***

By the same token, and as only an aside comment, the opening sentence of Post #56 would encourage newcomers not to continuing reading this valuable conversation, and possibly they would miss the very valuable warning just given Post #80.

WW

[pnodrog]

I really liked Post #81, it made me think, (i.e. think back in time), thanks.

(continuing the theme of my last post) That's akin to what we did with film - what I mean is:

Traditionally we'd use Circle of Confusion as the base for Diffraction and Depth of Filed. CoC being dependent upon the Camera Format, aka colloquially 'Film Size'. I am pretty sure, in fact, that was what we were taught, as theory, in my Diploma Courses.

However, in the real world and considering "Equivalence", different Film Emulsions have different characteristics, additionally those characteristics, as they would appear to the Viewer's Eye in the FINAL PRINT, could be manipulated by (not limited to): Exposure (i.e. under or over); Development Time; Development Temperature; Medium on which the Print was made (simple example, different Paper Grades).

***

Personally I find the concept of “Equivalence” firstly interesting and secondly (more importantly) very useful.

I think Paul’s comments are quite harsh and (more importantly) inaccurate.


Yep, being sceptical promotes thinking and debate and more often than not learning.


Yep, some camera reviewers have absolutely no idea what they are talking about and they use what they consider as their acquired knowledge to make all sorts of silly claims and statements. And obviously different Cameras Formats are not on an equal footing. But it is not accurate to state that the concept of “Equivalence“ is initiated by reviewers nor to imply that’s the only purpose of the concept.

The concept of “Equivalence” can be very useful, as one of many markers, when comparing and contrasting Camera Formats and the Lenses and Cameras which are available to use in those different formats.

As a really simple example – “Equivalence” can show us very quickly, just as my colleague Paul explained in 1980, that 135 Format Camera is still king if the Photographer is passionate for very shallow depth of field imagery.


A bit harsh and also generalizing, as well as speaking for others’ opinions.



Of course we cannot dismiss Shutter Speed and ISO.

But “Equivalence” as I perceive the whole concept doesn’t ‘ignore’. At some stages in the process of the using "Equivalence" we might ‘not include’ Shutter Speed and ISO. For example the simple comment above, ““Equivalence” can show us very quickly . . . that 135 Format Camera is still king if the Photographer is passionate for very shallow depth of field imagery.”, that statement does not take into account ISO or Shutter Speed; nor does it take into account other elements which Photographers may consider to be critical for their own particular needs, e.g. any particular Lens’s sharpness when wide open; Size and weight of the Camera and Lens, etc

***

The way I think about “Equivalence” is that it is one part of the whole, and it can be very good guide for choice making.

In so far as anything being a guide for me making practical choices in the field: to get what I want in my Photography, I’ve always found it useful to limit variables of any theory that I have acquired.

For example, we can (and many forums have) debated the topic of Depth of Filed, until Mrs Brown’s cows come home – and that debate will go on for years and years.

Of course one key variable in (the final) DoF (as SEEN by the Viewer) is the PRINT/IMAGE SIZE – and another is the VIEWING DISTANCE . . . but thinking about all those variables really hurts my head when I am making pictures . . .

What I USE from the THEORY is this: With my 5D cameras at F/2.8, I will have 6 inches DoF for an Half Shot - that’s Nose to Ear, focus on Leading Eye, and if grab one of my APS-C Cameras, then I need F/1.8 to get the same.

Understanding the theory and then taking ONLY (what I consider the useful bits for me) to make Photos means that I have fewer brain aches and much more brain function to concentrate on other stuff, which is really important.

WW

Was I harsh?... The first time I came across the term it was used in a review by a reviewer who obviously supported the equivalence concept. Unfortunately when comparing a micro 4/3 camera with a FF camera he went on to say that due to the fact you would need to stop down with the FF camera to achieve the same DOF resulting in a longer exposure, that the micro 4/3 sensor was therefore effectively more sensitive to light. It was a gross misrepresentation and completely misleading to anyone silly enough to follow his advice and making a purchase decision on the basis of his review.

Unfortunately "Equivalence" is a concept so easily misunderstood by a novice for it to be of any great assistance to them making a camera purchase decision. Obviously if after years of using different format cameras I get it wrong there is little hope for a novice. There are no shortcuts to knowledge and experience. It's a bit like trying to develop an equivalence system to compare cars, SUVs and trucks. They are different not equivalent.

As William has pointed out there are occasions when the concept of equivalence in photography has some use but in the main it is open to so much misunderstanding that it is of very dubious benefit for the people camera reviewers think need it to help in comparing cameras.

[xpatUSA]

I really liked Post #81, it made me think, (i.e. think back in time), thanks.

(continuing the theme of my last post) That's akin to what we did with film - what I mean is:

Traditionally we'd use Circle of Confusion as the base for Diffraction and Depth of Filed. CoC being dependent upon the Camera Format, aka colloquially 'Film Size'. I am pretty sure, in fact, that was what we were taught, as theory, in my Diploma Courses.
WW

Bill, I see the CoC as somewhat like "the time" which, as you know is, whatever Chuck Norris says it is ...

Myself, I've given myself quite a bit more DOF simply by using a CoC based on my poor vision gazing at my 24" monitor at about 45cm distance - as opposed to the traditional 8x10" print held 25cm from my nose.

Of course, someone gazing at one of my shots on their 4K monitor with their perfect vision would not see the same as me.

[William W]

Was I harsh?... . . .

Yes. But not as harsh as you could have been.

I read the more recent response has much less harsh. It begins to put squarely the blame where the blame is due: on the dingbat class of camera reviewers.

I agree that the person who wrote – “due to the fact you would need to stop down with the FF camera to achieve the same DOF resulting in a longer exposure, that the micro 4/3 sensor was therefore effectively more sensitive to light.” Would be indeed in that ‘dingbat’ category.

*

Your position now is indeed much less harsh – if it were still harsh, the last para. would have read something like this:

As William has pointed out there is the odd occasion when the concept of equivalence in photography has some limited use but in the main it is open to so much misunderstanding that it is of extreme doubtful and dubious benefit for mostly all people, everywhere.

It's nice that you are less harsh now - perhaps we should talk Cricket or Rugby, whilst you are less harsh... BTW my younger daughter and her friend arrived in Christchurch last night, they're driving around the South Island - you Kiwis take good care of them... and turn up the heater, please!

***

On a tad more serious note – I agree that (many) Camera Reviewers make a mess of things... as one example I have seen one reviewer using a focus testing chart (the type used to test front and back focussing when using AF, for those not familiar look it up it it’s the test where you set the chart at 45 degrees to the Lens’s Axis and AF on the centre black bar of the chart).

Anyway this dingbat was setting the camera on a tripod and shooting down at the chart laying on the floor – i.e. FLAT to the Camera / 90 degrees to the Lens’s Axis.

My point being, just because this fellow had little idea of what to do with a practical application of the concept of Front and Back Focussing when using AF and he was spreading just dumb information – I don’t think we should take the stand to eradicate the concept of Front and Back focussing when using AF.

Akin to “Equivalence” - Front and Back Focussing when using AF, really doesn’t matter one hoot to that many photographers and there is much misinformation about it on the WWW and the concept may confuse beginners, especially confuse them into thinking that their gear is garbage and that they have a ‘poor copy’, when probably, in ninety-five percent of cases it’s not the lens front or back focusing - but it is poor user technique.

WW

[William W]

Bill, I see the CoC as somewhat like "the time" which, as you know is, whatever Chuck Norris says it is ...

Between Paul and you backing him up, I'm going nuts down here.

Of course the 'Circle of Confusion' is exactly what Chuck says it is - so is everything: always has been and always will be.

It is all perception, Dr Ethan Powell teaches us that.

You fellows have a great weekend - and make lots of nice photos.

Bill

[pnodrog]

Bill I must remember to try and be more agreeable especially as my Son in Oran Park has suggested we live there too. We would almost be neighbours and you may come and take unflattering photos of me (not a big challenge) and post them here as punishment...

A good weekend to you as well.

[george013]

....................
On a tad more serious note – I agree that (many) Camera Reviewers make a mess of things... as one example I have seen one reviewer using a focus testing chart (the type used to test front and back focussing when using AF, for those not familiar look it up it it’s the test where you set the chart at 45 degrees to the Lens’s Axis and AF on the centre black bar of the chart).

Anyway this dingbat was setting the camera on a tripod and shooting down at the chart laying on the floor – i.e. FLAT to the Camera / 90 degrees to the Lens’s Axis.

My point being, just because this fellow had little idea of what to do with a practical application of the concept of Front and Back Focussing when using AF and he was spreading just dumb information – I don’t think we should take the stand to eradicate the concept of Front and Back focussing when using AF.

Akin to “Equivalence” - Front and Back Focussing when using AF, really doesn’t matter one hoot to that many photographers and there is much misinformation about it on the WWW and the concept may confuse beginners, especially confuse them into thinking that their gear is garbage and that they have a ‘poor copy’, when probably, in ninety-five percent of cases it’s not the lens front or back focusing - but it is poor user technique.

WW

Maybe he was just checking the sharpness/quality of the lens. Then you need this set up.

By the way, focusing on a plain not perpendicular on the optical ax is always introducing a miscalculation since the sensors have a size. Focus on a plain perpendicular to the optical ax and do the readfing from a measuring rot placed under an angle.

Just to put in perspective your writing. I can't check it.

George

[joebranko]

Well I finally but the bullet and made my decision. I am staying with my crop frame!
I today purchased a 77Dcrop frame Canon 24 mpx. Have not used it as yet....

[billtils]

Well I finally but the bullet and made my decision. I am staying with my crop frame!
I today purchased a 77Dcrop frame Canon 24 mpx. Have not used it as yet....

Congrats Joe - enjoy!

[photomaen]

These two points are inconsistent. To define either diffraction or out of focus blur one can use either a circle of confusion (which depends on the sensor size) or a pixel size (which does not depend on the sensor size) as the area to which the blur should be limited to produce a sharp image. Traditionally people use CoC for both diffraction and DOF. For example, Joseph James says: "The [equivalent] photos all have the same DOF (as well as diffraction softening) when they are taken from the same position with the same focal point and have the same display size." He repeats this quite a few times on his page.

Bob Atkins shows a table to demonstrate how to keep diffraction softening constant across different formats when printing 8 x 10:

http://www.bobatkins.com/photography...ffraction.html

So, if we agree to use CoC that normalises images taken with different cameras to a given output format (e.g. 8 x 10 prints), then the answer to questions 3 and 4 is YES.

If we use a pixel size as a reference and view our images at 100% magnification, then the answer to both questions in NOT NECESSARILY. Many DoF calculators allow you to switch from the traditional CoC approach (that does not take into account Mpx count) to the pixel-peeping approach (for which you need to enter the number of Mpx in your camera). Then they simply shrink CoC value to match that number of megapixels and report back a much narrower DOF for the same shooting scenario.

There is a tutorial on CiC that explains when one can detect diffraction softening as the lens is stopped down. The smaller the pixels, the sooner one can see some softening at 100% magnification. This does not mean that this softening will be detectable in 8 x 10 prints, for example.

Thanks for your replay, I am looking to buy a good camera with full specifications, can anyone help me ?

[William W]

Well I finally but the bullet and made my decision. I am staying with my crop frame!
I today purchased a 77Dcrop frame Canon 24 mpx. Have not used it as yet....

... been four weeks...used it yet?
how is it?
WW

[William W]

Thanks for your replay, I am looking to buy a good camera with full specifications, can anyone help me ?

What cameras and lenses do you have now?
What do you want to photograph?
What experience do you have?
What's your budget, roughly?
Any other factors that are relevant?

Probably better to begin a new conversation with a question containing much more detail about you and about what you want to achieve with your photography.

WW

[joebranko]

... been four weeks...used it yet?
how is it?
WW

Yes I have! Will be posting some pics taken with it soon I like to think it is producing cleaner clearer pics than my T2i, but thats just me...

[William W]

. . . I like to think it is producing cleaner clearer pics than my T2i, but thats just me...

Fantastic!

Of course it is producing better results! Don't dismiss the very high probability that you're putting more effort, enthusiasm and thought into each shot BECAUSE you have just bought a new camera.

WW

[rpcrowe]

If you want to stay with Canon you should take in consideration another difference between Canon crop and full frame cameras.

The top line crop sensor camera is the Canon 7D2 which should be soon replaced by a newer model.

If you were contemplating the purchase of a Canon full frame camera at approximately the same price as a 7D2, you would be looking at a Canon 6D2 - which is certainly not a top line camera by any means.

While a company like Sony is competing with the other camera companies for predominance, Canon competes with Canon and has such a fear that a lesser priced camera will cut into the sales of their flagship full frame cameras that they stripped the 6D2 of so many features that it is barely adequate for many uses.

Sony, on the other hand, is offering the 7Diii at the original price point of the Canon 6D2 (Canon has drastically reduced this clunker because of low sales resulting from the inadequacies of the camera) and has, despite Sony designating this camera as an "entry level full frame camera" (the same designation that Canon placed on the 6D2), a great many features and few inadequacies. Sony has not "dumbed down" the A7iii so it won't compete with the A7Riii or the A-9. In fact, Sony has added many of the attributes of the A-9 into the "entry level" A7iii.

I have both a 7D2 and a 6D2. The 6D2 has many nice qualities but also so many inadequacies that I find myself using my 7D2 more often than the 6D2. I expected this to be the other way around.

Canon "could" have introduced a wonderful camera with the 6D2. It has many qualities which endears it to me but, also has so many inadequacies that I simply could not recommend that camera to anyone as a general purpose, all-around shooter.

If you wanted to "buy new" and to get a completely functioning Canon full frame camera, IMO, you would have to spring for the 5D Mark IV. However, the price of a new 5D4 at B&H is over $3,000 U.S. Dollars which may or may not be more that you desire to pay... The 5D Mark III runs about $2,000 as a Canon factory refurbished item but, is not quite up to the standards of the 5D Mark IV.

If I were contemplating a full frame camera to replace my 6D2 (which I am seriously thinking about now) I would look at the Sony A7iii at about $2,000 USD. Otherwise, if I were you, I would wait until the Canon 7D Mark III makes its debut. However, judged by Canon's past performance with the 6D and 6D2, the 7D3 may not be a great improvement over the 7D2

BTW: Although I have done most of my shooting with crop sensor cameras (10D, 30D, 30D 7D and 7D2), the only EFS lens that I own is the 17-55mm f/2.8 IS. I do own a Toina 12-24mm f/4 Mk.I but that lens, while designed for a crop sensor can also be used on a full frame sensor down to about 17mm. So buying new lenses was never a problem with me switching over to full frame...

[xpatUSA]

While a company like Sony is competing with the other camera companies for predominance, Canon competes with Canon and has such a fear that a lesser priced camera will cut into the sales of their flagship full frame cameras that they stripped the 6D2 of so many features that it is barely adequate for many uses.

Good point.

I am reminded of my early Adobe days when Camera Raw (4.?) had so many functions "missing" compared to the same item bundled with other upper-end Adobe products. Shoot, it couldn't even handle 16 bpc images, IIRC ...

[joebranko]

Thanks for this Richard . I decided and purchased the Canon 77D so I am no longer in the market for a new camera. Anyway i appreciate your comments. Thanks again.