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Discussions about cameras, lenses, accessories, and image-processing.
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TOPIC: DPP4: Digital Lens Optimizer

DPP4: Digital Lens Optimizer 3 years 4 days ago #367

  • Andrew Browne
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In the process of familiarising myself with DPP4, I purchased the iBook "The Photographer's Guide to Canon Digital Photo Professional 4.0" by Hazeghi & Morris.
They state: "....Canon prime, super-telephoto lenses are so close to optically perfect that they do not require the use of the DLO.....As a general rule of thumb, any combination of Series II super-telephoto lenses and Series III extenders do not benefit from the application of DLO."
But then they go onto state in regard to the Canon prime, super-telephoto lenses".....With theses lenses it is recommended that you need only adjust the settings for Peripheral Illumination and for Chromatic Aberration" but the best way to enjoy the benefits of both is "........to enable in camera. It is recommended that you keep both enabled at all times".
When I try to enable these settings on my 5D 111 (Firmware 1.3.3) with my 600mm f/4 II lens attached, I get the message "Correction data not available".
I'm unsure in my case that in regard to what they state that , in the Perform Image Lens Correction, I should have the DLO enabled at the 50 setting, and/or the Peripheral Illumination and Chromatic Aberration enabled but at what starting setting?
Trust this makes sense, and perhaps someone like Ian Wilson may care to comment.
Cheers AB
Cheers AB

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Re: DPP4: Digital Lens Optimizer 3 years 3 days ago #368

  • Glenn Pure
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Hi Andrew


I'm sure Ian Wilson and others more expert in DPP and who are using similar high end lenses can comment. My understanding is that DLO doesn't just correct for lens deficiencies but also the effect of softness introduced in camera, particularly by the anti-aliasing filter over the sensor (that the 5DIII and most cameras have). Have a look at the post below as it gives a bit more info and implies the iBook you have isn't quite on the mark. I'm assuming the quotes from Canon below are accurate but haven't checked. Also, I'm guessing here, but suspect that even on the very best lenses, chromatic abberation will be hard to eliminate completely. For those situations where it does arise, I'd expect DLO to be the best possible way to fix it. That's certainly what I've seen with my lesser lenses.


http://www.dpreview.com/forums/post/54006593


"For those few images where you REALLY need to squeak out that little extra resolution, simply use DPP's DLO function. Here are some quotes from Canon Japan's website about DLO...


After passing the lens and before reaching the imaging element, the light beam is routed through filters designed to cut the infrared and ultraviolet spectrum as well through as low-pass filters to reduce moir? stripes. The low-pass filter, that affects image quality, cuts high frequencies (high spatial frequencies = delicate patterns) and plays an important role in avoiding the moir? effect.

Eliminating the low-pass filter would result in better image sharpness, but shooting would have to be done taking individual objects and situations into consideration. In other words, the camera system would lack proper balance to enable its usage in different situations.


*source: http://web.canon.jp/imaging/dlo/factor/index04.html


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.


*source: http://web.canon.jp/imaging/dlo/effect/index.html


There's a lot more to that site than just the above quotes. Take a look. DLO is, IMO, an underappreciated feature of DPP and is (I'm guessing) why Canon has released DPP 4 - to HOPEFULLY convince Canon users to utilize this tool when necessary rather than depending on 3rd parties to "fix" image quality issues arising from Canon cameras and lenses. Because given Canon's focus on video, I just don't see them getting rid of the AA filter. They might, but it would surprise me."


RE your lens correction in camera, I've not used this as I rely on DPP to do that job. I suspect you will need to download the data to your camera, probably through the Canon software interface 'EOS utility' (that I suspect you may not be using) to get this to work. Again, others more expert can comment.


Hope that helps.


Cheers

Glenn

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Re: DPP4: Digital Lens Optimizer 3 years 3 days ago #369

  • Ian Wilson
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Hi Andrew,

I am very pleased to see you are giving DPP4 a try. Glenn has given you a fulsome reply and I agree with all he has written. Arash Hazeghi is a very fine photographer and technical expert but in regard to the DLO he is not quite on the money. The DLO is useful, even when using super-telephotos, because it helps to remove blur due to residual aberrations (an issue for wide apertures and with extenders), diffraction (always present) and the camera low pass filter (AA filter). There is always some benefit using the DLO, even if the lens is perfect, because diffraction is always present and the optical low pass filter introduces some blur. The Canon Japan information describes how the DLO works in terms of the total optical transfer function and how this is used to de-blur the image in an inverse operation that mathematicians call deconvolution.

Regarding the in-camera peripheral illumination (vignetting) correction, chromatic aberration etc, Glenn is correct in advising that this data may need to be downloaded from a Canon website. Your camera comes pre-loaded with some lens data but may not have your particular lens and extender combination. I needed to do this with my old 5DIII but do not remember the details; I think Glenn is correct when he writes that you need to use the EOS Utility software. You should enable in-camera peripheral illumination correction and chromatic aberration correction. However, when you use the DLO, the chromatic aberration correction will automatically turn off as the chromatic aberration is already included in the lens data downloaded for the DLO.

Hope this helps, it is well worth persevering. Good luck and best wishes,

Ian

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Re: DPP4: Digital Lens Optimizer 3 years 2 days ago #370

  • Andrew Browne
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Thanks Glenn and Ian
The advice from both of you is once again greatly appreciated. As suggested I've downloaded EOS Utility and am currently downloading the required data for my 600mm II and extenders, and will push on from there.
Looking forward to catching up with you Ian at the Melb Bird Photo Group meeting on 27th, unfortunately i'm not back from Tassie in time for the Westernport outing.
Cheers Andrew
PS: download and camera upload successful, and Lens Aberration Correction now enabled in camera!
Cheers AB

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Re: DPP4: Digital Lens Optimizer 2 years 11 months ago #374

  • Ian Wilson
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Hi Andrew,

I just happened to come across this interesting interview with Chuck Westfall, technical adviser, Professional Engineering & Solutions Division, Canon USA http://www.arihazeghiphotography.com/AH_CW_interview/

The interview was conducted in 2012 at the time the 5DIII was released and when the DLO was introduced to DPP. He explains the advantages of using the DLO and provides other information that will be of interest to 5DIII owners.

Regards,

Ian



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