john_curlett

<p>This is longitudinal CA where subjects in front of the plane of focus are purple and the those behind are green. It has nothing to do with the water droplets. It will improve if you stop it down. Some copies of The Micro Nikkor 105mm f/2.8G have absolutely horrible Lo CA. I know, I had one that I bought new. I wasn't usable as a medium telephoto because of this. I had to stop it way down to get the CA to an acceptable lever.<br> I sent it back to Nikon the day after I bought it and all they did tweaked the focus a little but didn't realign the lens. I talked to someone I know in NPS and she confirmed that this is a problem with this lens and some are much worse than others. I tested this lens against a "D" version and a Tamron 90mm, f/2.8. Both of these lenses had almost no Lo CA wide open. I sold the lens cheap just to get rid of it. It was by far the worst lens I have ever had in the nearly 50 years of shooting "pro" glass.<br> Sorry about the rant. It still makes me mad to this day.</p> <p>John</p>

<p>I have a D7000 that I bought as soon as they came out and love the camera. The focus on mine is spot on but I do mostly use the center point. I also have a D800 that I bought used with very low mileage from a friend that I love as well.<br> <br /> I had good DX lenses with the D7000 but I started my migration to FX by replacing the lenses one by one with pro level full frame glass. With each addition of a new lens I was more impressed with the performance of my D7000. When I finally got the D800 it didn't seem like that big of an upgrade. The sensors are very similar and the pixel pitch is the same so the images are identical except there is more of it on the D800. The main difference now is that I am gaining upper body strength carrying around the D800 and those big lenses.<br> <br /> I agree with virtually everything that has been said here. I just wanted to add that, in my opinion, the glass is more important than the sensor size. If you have really good glass, there is not that great of a practical difference between DX and FX.</p> <p>John</p>

<p>That is just how the camera works. In the default setting, the camera refocuses every time you half-press the shutter button whether the image is in focus or not. To prevent this, you need to either switch the lens and or camera to manual focus or disable the focus function from the shutter button and use one of the back buttons for auto-focus.</p>

<p>I find Ken a good source of information but you have to filter out a lot of things that are strictly his opinions.<br> </p> <blockquote> <p>I wouldn't worry about Rockwell--he's not an engineer or anything</p> </blockquote> <p>Regarding this comment:</p> <h4><a title="Find others with this title" name="title" href="https://www.linkedin.com/vsearch/p?title=District+Sales+Manager&trk=prof-exp-title"></a>District Sales Manager</h4> <h5><a href="https://www.linkedin.com/company/3241?trk=prof-exp-company-name">Tektronix</a></h5> February 1995 – February 2004 (9 years 1 month)Hollywood, California <p >Helped design sections of most of the major television network broadcast centers as well as motion picture and television post production facilities. I was Hollywood's go-to guy for measuring picture quality.</p> <h4><a title="Find others with this title" name="title" href="https://www.linkedin.com/vsearch/p?title=Senior+Applications+Engineer&trk=prof-exp-title"></a>Senior Applications Engineer</h4> <h5><a href="https://www.linkedin.com/company/3745?trk=prof-exp-company-name">TRW LSI Products Inc.</a></h5> January 1988 – January 1992 (4 years 1 month)La Jolla, California <p >Designed HDTV, digital imaging and audio DSP and ADC and DAC conversion hardware and integrated circuits and systems.</p> <h4><a title="Find others with this title" name="title" href="https://www.linkedin.com/vsearch/p?title=Chief+Engineer&trk=prof-exp-title"></a>Chief Engineer</h4> <h5><a title="Find others who have worked at this company" name="company" href="https://www.linkedin.com/vsearch/p?company=WPOB&trk=prof-exp-company-name"></a>WPOB</h5> September 1977 – November 1988 (11 years 3 months)Plainview, Long Island, New York <p >88.5 FM and KHC-94 microwave ITFS TV</p> <h4><a title="Find others with this title" name="title" href="https://www.linkedin.com/vsearch/p?title=Engineer&trk=prof-exp-title"></a>Engineer</h4> <h5><a title="Find others who have worked at this company" name="company" href="https://www.linkedin.com/vsearch/p?company=Litton+Guidance+and+Control+Systems+Division&trk=prof-exp-company-name"></a>Litton Guidance and Control Systems Division</h5> November 1985 – January 1988 (2 years 3 months)Woodland Hills, California <p >Designed ring-laser gyros for use on everything from commercial jetliners to Tomohawk cruise missiles and fighter jet ejection seats.</p>

<p>Also consider the Tamron 24-70mm f/2.8 which is cheaper than the Nikon and includes image stabilization. DXO rates the Tamron slightly higher (like one point) in all categories than the Nikon. I have one and am very pleased with it. As Shun said, they are large heavy lenses. but I think are worth it.<br> John</p>

<p>Note that the voltage of a car battery while the engine is running is around 14.5V and will sit above 12V immediately after the engine is stopped.</p>

<p>I have FoCal and use it along with the ruler with a focus mark as described above. I find the ruler method to be quicker and just as accurate as FoCal. It is very worth doing especially for the D800 where you will easily see the focus errors when viewed 1:1.</p>

<p>Andrew - I have read your responses several times and stand by my original comment. I would like to address your second paragraph:<br> "From a creative perspective, the depth of field of a DX camera is less than that of a longer lens of the same f-stop used on an FX camera."<br> Doing a quick calculation of a 50mm lens on a DX camera at f/4 with the subject 20 ft away will have a total depth of field of 8.04 ft. A FX camera with a 75mm lens at f/4 and a subject 20 ft away will have a depth of field of 5.22 ft. Clearly the DX camera has the advantage of a significantly greater depth of field.<br> I have no interest in arguing these points with you. It is what it is.</p> <p>John</p>

<p>I would like to correct a statement made earlier in this thread. The "speed" or F number of a lens does not change with the format of the camera. A f/2.8 full-frame lens will provide exactly the same exposure on a FX camera as it does a DX camera. The only difference is the smaller field of view on the DX camera because of the smaller physical size of the sensor.</p>