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| bio | website | jonrista.com |
|---|---|---|
| location | Denver, CO | |
| age | 33 | |
| visits | member for | 2 years, 10 months |
| seen | 8 hours ago | |
| stats | profile views | 1,757 |
I am a relatively new photographer, having been at if for only a few years. I chose Canon gear when I finally took the plunge into DSLR. I am an avid hobbyist now, and love everything about photography, from the gear, to the science, to the art. I spent years reading about the technology and photography theory, so I am very well versed in the technical aspects of photography. My artistic skills are moderate, but improving. You can see my work @ the following sites:
My interests lie primarily in nature photography:
- Birds
- Songbird Setups
- Shore Birds & Waders
- Raptors
- All others
- Astrophotography
- Moon
- Wide Field
- Deep Sky
- Landscapes
- Wildlife
- Floral Macro
- Insect Macro
- Abstract
I currently use the following gear:
- Cameras
- Canon EOS 7D
- Canon EOS 450D (Rebel XSi)
- Lenses
- EF 16-35 f/2.8 USM L Wide
- EF 50mm f/1.4 USM
- EF 100mm f/2.8 USM Macro
- EF 100-400mm f/3.5-5.6 IS USM L Zoom
- EF 300mm f/2.8 L IS II (Periodic rentals)
- EF 500mm f/4 L IS II (Periodic rentals)
- EF 600mm f/4 L IS II (Periodic rentals)
- Canon EF 1.4x TC III
- Canon EF 2x TC III
- Kenko 1.4x Teleplus Pro 300 DGX
- Filters
- Lee Foundation Kit (x2) + Tandem Adapter
- Lee .3/.6 ND
- Lee .3/.6/.9 Soft Grad ND
- Lee .3/.6/.9 Hard Grad ND
- Lee CPL
- Tripod
- Gitzo Systematic GT3532LS 3S. Series 3 Tripod
- Jobu Pro 2 Gimbal
- Gitzo Mountaineer GT0541 4S. Series.0 Tripod
- Gitzo GH1780QR Series.1 Mag. Center Ball Head
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May 3 |
comment |
Why is on sensor PDAF drastically slower than traditional PDAF? Hmm, one extra thing...there is the 50% loss from the half-silvered main mirror. Despite that, dedicated AF sensors still work with more light...at least 15% from a given lens region, which is still considerably larger than a single FPPDAF pixel's area. |
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May 3 |
comment |
Is it important that the Canon 1DX isn't specified to autofocus with lenses slower than f/5.6? Seeing as the 1D X now does focus at f/8 with the latest firmware, I believe this question is now obsolete. As such, I am going to close it, and it may potentially be deleted in the future. |
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May 3 |
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What is the best order to set exposure parameters (ISO, aperture, shutter)? I am not sure this question is a good fit. There is no way to correctly set exposure...as the answers indicate, what you change really depends on what you are photographing and what your goals are. There is no correct answer here, and any answers that try to be "correct" will only mislead you. |
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May 3 |
comment |
Why is on sensor PDAF drastically slower than traditional PDAF? Finally, lens drive is an external factor, and does not actually have anything to do with the phase-detection mechanism. The communications algorithms used between lens and body (and the AF drive firmware) would be the same regardless of whether it is FPPDAF or Dedicated PDAF...the outcome of both is the same: Move the lens X direction by Y amount, check that the move was performed and the distance of change was correct, (possibly repeat if closed loop and the distance moved was not enough/too much.) |
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May 3 |
comment |
Why is on sensor PDAF drastically slower than traditional PDAF? A dedicated PDAF sensor has more light to work with. For one, instead of 50% of the light for a given pixel, each strip works with 50% of the light for that entire region of the lens, thanks to the AF Unit's splitting and focusing lens. Right off the bat you have more light to work with. On top of that, the photo diodes of each AF sensitive strip are much, much larger than the average sensor pixel. Tens of microns. Overall light sensitivity is much higher. There is no color filter, so you aren't losing any additional light. |
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May 3 |
comment |
Why is on sensor PDAF drastically slower than traditional PDAF? You also need to account for the quantum efficiency of sensor pixels, vs. dedicated PDAF sensors. Quantum efficiency of sensor pixels is around 40-60%, and HALF the pixel area is receiving light (remember, they are masked), so not only do you lose 30-40% of the light from the filter, you lose 50% of the light before that from the masking, and another 40-60% of the light because of efficiency losses. Each PDAF pixel in a sensor is only working with ~8.8% of the grand total amount of light that makes it through the sensor and onto those pixels! |
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May 2 |
comment |
For MTF, why does 10 represent contrast while 30 represent resolution? Aside from the kind of coating used on a lens to mitigate reflections (which are the primary thing that can reduce contrast...ghosting, flare, etc.), the materials used to make the lenses also affect overall transmission. High grade optical glass is designed to have not only high resolving power, but also high transmission. Poorer quality glass, such as that used in mass-manufactured consumer grade lenses, often has more impurities which absorb light, rather than transmit it. The larger 10lp/mm test aims to determine the overall transmission of a lens...as low transmission reduces contrast. |
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May 2 |
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For MTF, why does 10 represent contrast while 30 represent resolution? @erotsppa: You almost have it. You are correct on resolution and small lp/mm. When it comes to contrast, that is really more of a measure of a lens' ability to transmit light. Aberrations would affect resolution more, similar to diffraction. They could reduce contrast, and things like CA will reduce contrast. But for the most part global contrast is a matter of transmission and flare control. With no coatings, transmission can be fairly low...as little as 30%. With a single coating that can jump considerably, to 70%. With multicoatings, transmission is between 70-90%. Nanocoatings, 99.5%+. |
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May 1 |
comment |
Deep Sky Photography with telescope without Tracking Enjoy the deep night sky with your eyeballs! :) You could probably get some pretty sweet shots of the sun as well, if you use proper filtration. |
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May 1 |
answered | Deep Sky Photography with telescope without Tracking |
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Apr 30 |
comment |
cameras with remote shutter releases other than DSLR types I am not sure we should be so ready to write this off. It does sound like it is a remote shutter release app that works with both DSLR and non-DSLR cameras. While the OP did ask about "cameras" that support remote shutter release, I don't thin that implies we should exclude the option of CHDK, Magic Lantern, or other software alternatives that might solve the same problem, so long as they work for non-DSLR type cameras. Menteblu did disclose the fact that he is promoting his own software, so this isn't a covert ad. I think we should give it a chance, and let the OP decide. |
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Apr 30 |
reviewed | Approve suggested edit on instagram tag wiki |
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Apr 30 |
reviewed | Approve suggested edit on instagram tag wiki excerpt |
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Apr 30 |
comment |
For MTF, why does 10 represent contrast while 30 represent resolution? @erotsppa: Do you have any further questions? Before I update the answer, I want to make sure I've got everything covered... |
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Apr 30 |
comment |
For MTF, why does 10 represent contrast while 30 represent resolution? Resolving power drops because the lens is causing a lot of blur wide open. The MTF chart doesn't contain enough information to tell you why it has a lot of blur, or what kind of blur it is...there is not enough information in an MTF about whether blur is caused by diffraction or optical aberrations specifically. The only measure of optical aberrations is really whether the lens produces identical image quality across its total surface area (the "rotational" factor...astigmatism, and focal plane...field curvature, neither of which are really affected much by aperture, not like CA et. al.) |
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Apr 30 |
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For MTF, why does 10 represent contrast while 30 represent resolution? @erotsppa: Resolution is lost as blur increases, and as blur increases, microcontrast at those fine detail levels drops. A loss of global contrast can be due to poor transmission by the lens, which cannot fully transfer the original signal in total accuracy. Again, it IS all about "contrast", but multiple things can have an impact on contrast, and affect contrast at different levels. At 10lp/mm, the lens has good to excellent contrast midway to the edge, you read that correctly. At 30lp/mm, the lens has poor to good resolving power, you also read that correctly. |
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Apr 29 |
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For MTF, why does 10 represent contrast while 30 represent resolution? @mattdm: I've rewritten my answer. Hopefully this is better |
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Apr 29 |
revised |
For MTF, why does 10 represent contrast while 30 represent resolution? Explained MTF chart with sample from Canon |
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Apr 29 |
revised |
For MTF, why does 10 represent contrast while 30 represent resolution? added 8782 characters in body |
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Apr 28 |
comment |
Why are Zeiss lenses heavier and larger for Canon EF than Nikon F mounts? I would like to know the same thing Matt asked. Could help a lot in offering a valid answer. |
