burkphoto Loc: High Point, NC

Diffraction occurs with high megapixel, high density sensors when very small apertures are used. The smaller the sensels (individually filtered, light sensor elements), the worse the phenomenon.

It looks like everything is fuzzy, as if you used a soft focus filter. The image has great depth of field, but nothing is truly sharp. Contrast suffers, too.

Chris T Loc: from England across the pond to New England

Bill - is there a "norm" for a sensor, before it becomes a "high megapixel, high density sensor" ???

If so, would it be - above 12mp, for instance? ... 16MP, 18MP, 20MP, 24MP, 26MP, 30MP, 36MP, 42MP, 50?

I'm interested to know if there's a demarcation line, which acts as a trigger for what you describe?

Chris T Loc: from England across the pond to New England

Bill - the 15MP Canon Sensor - departed with the EOS 50D - and good riddance to it, and all!!!

The 18MP Canon Sensor - is still with us, in one or two models, but the 20MP sensor replaced it, and that was, in turn - replaced by the 22MP sensor, and then the 24MP sensor, and now the 30MP and 50MP ones.

The new FF 6D Mk. II - however, has started a new trend - sporting 26MP. So, clearly - Canon isn't worried about this diffraction-diffusion biz caused by "high megapixel, high density sensors" … now, are they?

And, now, there's even talk they will soon bring a 100MP sensor - to FF as well!!!! … How 'bout that???

Chris T Loc: from England across the pond to New England

Bill - judging from this response, then - it would seem - if you use the 12MP EOS Rebel T3 (one of mine) or the Nikon D300S (DX), or the Nikon D700 (FX) - you're home free, then … and will NOT be plagued by this "diffraction-diffusion" problem inherent in "high-density, high resolution" sensors which start at 15MP and above? … (Since all of the above have 12MP sensors.) … And, can happily click away at f32, or f40 (on some lenses) or at f45, even? … So, that'll be good then. Think I'll look around for one of those older N's!!!

burkphoto Loc: High Point, NC

There is seldom a good reason to use apertures smaller than f/16 on full frame, f/11 on APS-C, or f/8 on Micro 4/3. Most lenses perform at their best at medium apertures (one to three stops down). If you put a decent depth of field calculator on your smartphone, you can nearly always find a good compromise between depth of field, focal length, and aperture choice for the format and lens in use.

I photographed a group of about 100 people a few weeks ago. I was able to get them all in relatively pleasing focus at f/6.3, just beyond the limit of barely detectable diffraction on my 16MP Micro 4/3 sensor. That was for a 30x20 print...

Many older photographers grew up in the era of large format (4x5 inches and larger) and large medium format (6x7 and 6x9cm) cameras. Diffraction was always there, but magnified one HUGE amount less, so you could use f/64 or f/128 on 8x10 without really seeing it. Unfortunately, old habits die hard.

Just because we needed f/22 on medium format to get a lot of depth of field in a group photo DOES NOT mean we need f/22 — at least not often — on Micro 4/3. That's why the Leica-branded Lumix lenses don't even include apertures smaller than f/16. Leica knows better!

To render the same *field of view* on smaller formats, we use *shorter* lenses on them. A 24-70 on full frame provides the field of view range of an 18-55 on APS-C or a 12-35 on Micro 4/3. So f/16 on full frame at 50mm performs much like f/11 on APS-C at 35mm or f/8 on Micro 4/3 at 25mm... in terms of rough depth of field equivalence AND diffraction. And f/22 on 6x4.5cm has roughly the same depth of field at 75mm as f/16 on full frame digital or 35mm film.

Chris T Loc: from England across the pond to New England

Well, I don't have a cellphone, Bill - so that calculator dealie is out! … But, it is most certainly gratifying to see you DO support f11 on an APS-C camera - since that's all I use. But, one of my cameras - I think it's the 16MP Pentax K-50 - upon which I use the Tamron 18-200 XR - which seems to frequently employ f40 in good light. I also tend to use my 12MP EOS Rebel T3 on the A-Dep setting, which automatically shuts down the aperture to the smallest setting available, depending on lighting conditions - which, with the Tamron 18-270 VC PZD I use on that one - more often, than not - utilizes f32, when possible. So, maybe these two cameras, anyway - know better than you? … Or, perhaps, I'm winding up with fuzzy pics … which?

k2edm Loc: FN32AD

thaank you... Ed

RichardTaylor Loc: Sydney, Australia

"Fuzzy pics" can be caused almost by anything, including diffraction.
Posting some exemples, with downloading enabled, along with the exif data, may help us analyse the problem and suggest a solution.

Chris T Loc: from England across the pond to New England

Richard - I don't have a problem with fuzzy pics … that's exactly what I mean, you see. It's Bill's assertion, one will wind up with fuzzy pics due to this diffraction-diffusion - caused when using high-megapixel, high density sensor cameras (15MP and above - according to him) - with lenses which shut down beyond f11.

You know, Richard - it really helps - if you wish to contribute to a thread - you read the whole thing, before adding to it … and then - you won't seem out in left field ….

RichardTaylor Loc: Sydney, Australia

User ID

CT, your disregard for U-Hog tradition is
not earning you many admirers. A few
perhaps, but a rampant epidemic of RCI
put the traditions so deeply embedded
... pardon that supreme pun ... that any
sufferer's chances of recovery are rather
less than zero.

Chronic RCI is not necessarily fatal, but
always, ultimately, terminal. It's truly a
dark prognosis ... damn, punned again.
For a better understanding of RCI, and
challenges facing the afflicted, please
follow this link:
https://www.urbandictionary.com/define.php?term=rectal%20cranial%20inversion

Always remember:
Understanding is the
key to understanding.

And oh, just to stay On-Topic, OP must
bag a 24-70. All of the kool kids do it.

.

Chris T Loc: from England across the pond to New England

I don't think so, USER … don't need one, nor can I afford it … I've got that length covered, on each and every system I use …. and, who says I'm a "Kool Kid" anyway … ???

I am way past - being a KID … no matter, HOW you slice it!!!

And, as far as the way I communicate with my very best friend here on UHH - it's none of your damned business … so stay the heck out of it!!!!

User ID

`

The Kool Kids are ageless !

OTOH, if I overlooked a bromantic
exchange, well, hey ... get a room !

As to a 24-70 for the OP, what you
can afford is not relevant to the OP.
You are you. The OP is the OP. He's
a top candidate for the Kool Kids !

.

Chris T Loc: from England across the pond to New England

It's not like that, but Richard always seems to appear whenever I do a new Topic Post or make a comment
… for well over a year, now … he's the only one who seems to care about whatever I've got to say ….

I hadn't looked to see if this Post was one of mine. Now, I have, and I see it isn't … paaaaardon ME!!!

User ID

Awwwwww ...... Group HUG !