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Can an in-camera Sharpness setting compensate for the Low-Pass filter?

PajamaGuy
Enthusiast

I've been trying to find the unfindable magic key to sharp pics (there seem to be many of them) - and I keep coming back to the thing I can't control; the Low-Pass filter on the Rebels.  I just read Canon guru Rudy Winston's article on the EOS D-SLRs - and would basically like to see what the images would look like without the filter (since I don't shoot a lot of fabrics with fine, repeating patterns).

 

So, my question is, "Can I create a custom Picture Style that would compensate for the loss of detail caused by the low-pass filter, and if so, what settings would I use?"

 

Or, since the sensor's low-pass filter is a constant, could I create an un-sharp mask that would effectively remove the low-pass filter's modifications?

 

Thanks!

PJ
(Grampy)



"Photography is a money-sucking black hole, and I'm approaching the event horizon"
12 REPLIES 12

TTMartin
Authority
Authority

If you shoot RAW, Canon's Digital Lens Optimizer in Canon Digital Photo Professional  is designed to compensate for the AA filter.

 

Principle of the Digital Lens Optimizer

 

DLO.gif


After passing the lens and various filters, the light has diverted from the ideal condition as it reaches the image sensor where the image will be formed. This is due to the influence of factors such as aberrations, diffraction, and the low-pass filter. If these influences can be compensated for using highly precise and specific data, the result ideally would be the original and optimal image. This is the unique principle behind the Digital Lens Optimizer. Factors contributing to optical image deterioration as the light passes through the lenses and filters in the camera were identified and converted into mathematical functions (optical transfer functions (OTF)). By applying the inverse functions to the captured image, the state of the light (image quality) can be returned to approach the state that the incident light had before entering the camera.
The factors such as aberrations, diffraction, and low-pass filter influence differ for different lenses and cameras, and they also are dependent on shooting parameters. The Digital Lens Optimizer therefore uses inverse functions that are carefully optimized and based on precise data. This makes it possible to compensate even for complex and asymmetric aberrations such as coma.

Thanks for the replies!

I understand  the DPP and the RAW scenario - and I'll try to remember to switch to RAW when not shooting grandkids' sports.

 

...but I shoot mostly JPG because I  need the Burst Rate.  Yes, when I can afford it, I'll get a 7d  MKII which can maintain about 3.5 FPS RAW after the initial 2.8 seconds @ 10 FPS.  But for now, with my T6s, AND shooting grandkids, to capture a 3-5 second burst, I need JPG.

 

That's why I'm asking if & how I can compensate for the low-pass filter.  And thanks Ed, but surgery on my still-under-warranty T6s is not on my radar. 

 

Don't get me wrong, I think the combination of my camera settings and post processing does a pretty good job, and the resulting images vs those from my T3i are much better.  I'd just like to create a script that effectively negates the Low-Pass filter.

 

Thanks!

 

p.s. - Further reading enlightened me to the fact that Burst rate increases slightly when shooting RAW-0nly (without the "L") - I'll have to see if I really can get 8 at 5fps.  Judicious use of the trigger at only the key moments of a sequence may work - I'll try it when my T6s returns. (It's with Canon right now to find out why there's significant purple fringe with my EF 85mm f/1.8, and why the BBF sometimes triggers the shutter.)

 

PJ
(Grampy)



"Photography is a money-sucking black hole, and I'm approaching the event horizon"


@PajamaGuy wrote:

Thanks for the replies!

I understand  the DPP and the RAW scenario - and I'll try to remember to switch to RAW when not shooting grandkids' sports.

 

@...but I shoot mostly JPG because I  need the Burst Rate.  Yes, when I can afford it, I'll get a 7d  MKII which can maintain about 3.5 FPS RAW after the initial 2.8 seconds @ 10 FPS.  But for now, with my T6s, AND shooting grandkids, to capture a 3-5 second burst, I need JPG.

 

That's why I'm asking if & how I can compensate for the low-pass filter.  And thanks Ed, but surgery on my still-under-warranty T6s is not on my radar. 

 

Don't get me wrong, I think the combination of my camera settings and post processing does a pretty good job, and the resulting images vs those from my T3i are much better.  I'd just like to create a script that effectively negates the Low-Pass filter.

 

Thanks!

 

p.s. - Further reading enlightened me to the fact that Burst rate increases slightly when shooting RAW-0nly (without the "L") - I'll have to see if I really can get 8 at 5fps.  Judicious use of the trigger at only the key moments of a sequence may work - I'll try it when my T6s returns. (It's with Canon right now to find out why there's significant purple fringe with my EF 85mm f/1.8, and why the BBF sometimes triggers the shutter.)

 


Even with my 7D I typically try to time my shots and limit them to 3 or 4 in a burst. A lot of it comes down to knowing the sport and when the action will occur. Shooting softball and baseball simply watching the eyes fo the batter is usualy all that is needed to catch the ball in the frame and ball on the bat shots.

 

The purple fringing is a lens issue, and fairly typical of the EF 85mm f1.8. DLO will help with that too.

ebiggs1
Legend
Legend

Sometimes on some camera they can be removed.  Land scape photographers do it.  You really need a good camera repair shop and a filter pack to replace the low-pass.  I wouldn't do it.

 

Get up close and personal with a good post editor.  Smiley Happy

EB
EOS 1DX and 1D Mk IV and several lenses!


@ebiggs1 wrote:

Sometimes on some camera they can be removed.  Land scape photographers do it.  You really need a good camera repair shop and a filter pack to replace the low-pass.  I wouldn't do it.

 

Especially since models are starting to appear that don't have the low-pass filter.

 

Get up close and personal with a good post editor.  Smiley Happy


At the risk of being labelled a heretic, I suspect that any PP operation that isn't absolutely lossless will degrade sharpness more than the low-pass filter will.

Bob
Philadelphia, Pennsylvania USA


@RobertTheFat wrote:
At the risk of being labelled a heretic, I suspect that any PP operation that isn't absolutely lossless will degrade sharpness more than the low-pass filter will.

I'm fairly confident that Canon engineers know what is happening in the camera and Canon's DLO doesn't degrade the image.

 

If you haven't tried using DLO you should. It turns a pretty mediocre lens like the EF 24-105f f/4L IS into an outstanding lens. The results are truly remarkable.

 

But, then again DLO only works with files at the RAW level so it may fall into your definition of  'lossless'.

"At the risk of being labelled a heretic, I suspect that any PP operation that isn't absolutely lossless will degrade sharpness more than the low-pass filter will."

 

Bob from Boston, why is it you seem so hesitant to post editing?   Not to the heretic level ....yet.  Smiley Happy

 

With RAW you have access to sharpening and noise algorithms in a program like Lightroom 6, Photoshop with its ACR 9,  that are way more powerful than those found in your camera.

I am not so much a fan of DPP, as you know, but with the latest release of 4 and its latest incarnation, I can also recommend it. The DLO does work very well, indeed.

 

One must remember and realize it is not possibile to put anything back 'excatly' as it existed originally but these editors do a fabulous job.

 

Not to sound rude but to the OP, anybody that shoots jpg and not RAW is not really concerned on getting the best photographs!  

 

Also to the OP, the purple fringing is caused by the lens.  It is also very easily corrected with one of the above mentioned programs.  If the CA is very bad, it is a bad lens.  The lens needs to be looked at in that case.  IMHO, the 85mm f1.8 is a OK lens not a great lens.

EB
EOS 1DX and 1D Mk IV and several lenses!


@ebiggs1 wrote:

"At the risk of being labelled a heretic, I suspect that any PP operation that isn't absolutely lossless will degrade sharpness more than the low-pass filter will."

 

Bob from Boston, why is it you seem so hesitant to post editing?   Not to the heretic level ....yet.  Smiley Happy

 

I'm not in the least hesitant to edit my pictures. But I don't think editing should be oversold. My point here (maybe I didn't make it very well) was that a sharpening algorithm (which can, after all, enhance only the illusion of sharpness) may have a more detrimental effect on actual sharpness than the low-pass filter does.

 

With RAW you have access to sharpening and noise algorithms in a program like Lightroom 6, Photoshop with its ACR 9,  that are way more powerful than those found in your camera.

 

Maybe, but the ones in DPP are plenty good for my purposes. I rarely find myself in a situation where I have to rescue lousy shots; ordinarily I get to just pitch them. And the advantages of LR, whatever they are, aren't important enough to me to make up for the nuisance of having to deal with databases and sidecar files. And I freely concede that PS has a lot of capabilities that DPP lacks, but those capabilities don't seem to be particularly necessary to my style of photography.

 

I am not so much a fan of DPP, as you know, but with the latest release of 4 and its latest incarnation, I can also recommend it. The DLO does work very well, indeed.

 

DPP 4 is infuriatingly slow and buggy, but I'm still hoping it improves. I use it because it does a good job. I also still use DPP 3, because my wife's T2i still isn't supported by DPP 4.

 

One must remember and realize it is not possibile to put anything back 'excatly' as it existed originally but these editors do a fabulous job.

 

I trust DPP's ability to put things back like they were, but that's hardly the point. It's an editor's ability to undo the effect of a piece of hardware that's at issue.

 

Not to sound rude but to the OP, anybody that shoots jpg and not RAW is not really concerned on getting the best photographs!

 

Don't look at me if that's what you're thinking. I always shooi in RAW.

 

Also to the OP, the purple fringing is caused by the lens.  It is also very easily corrected with one of the above mentioned programs.  If the CA is very bad, it is a bad lens.  The lens needs to be looked at in that case.  IMHO, the 85mm f1.8 is a OK lens not a great lens.

 

It does sound as though the OP's lens has gone bad, although I guess that conclusion should be tested on another camera body. But that model is cheap enough not to be worth fixing, isn't it?

Bob
Philadelphia, Pennsylvania USA

Not to sound rude but to the OP, anybody that shoots jpg and not RAW is not really concerned on getting the best photographs!

 

You know....I was going to let most of the "Esteemed Contributer's" comments slide - but the above just ticks me off.   I guess I should preface my questions and board posts with a note that egotistical, self-proclaimed  "professionals" need not reply.  They really do not provide any constructive guidance to us mere JPG shooters and why would they?  Their ego-signatures proclaim their segregation form the lowly Rebel owners.  So why are they even in this sub-forum?

 

On the other hand, for those "Reputable Contributors" who desire to help us who mistakenly think we want to get better - thank-you, and keep it coming.

 

Sorry for the rant - but some folks...

 

Dave

PJ
(Grampy)



"Photography is a money-sucking black hole, and I'm approaching the event horizon"
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