RiceHigh's Pentax Blog: Does "Continuous AF" under Movie Mode of the Nikon D3100 Work?

Wednesday, September 29, 2010

Does "Continuous AF" under Movie Mode of the Nikon D3100 Work?

Tested by: http://www.eprice.com.tw/dc/talk/?prod_id=670&tid=12598 (in Traditional Chinese)

Judge by yourself for the subject question! I won't spoil anything! ;-) But if I have to compare to my NEX, then.. :-o

An ISO shootout is also included in the article, from ISO 100 to 12800, in one-stop stepping. Note that the D3100 and the Sony NEXes actually share the same sensor.

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arrkkkk · 754 weeks ago

OK..that sucks...

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rhermans · 754 weeks ago

I just don't understand that they dare to call that "Continuous".

1 reply · active less than 1 minute ago

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RiceHigh 110p · 754 weeks ago

Yes, it's really continuous - continuously to search for the focus! What actually do you want? ;-D

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Pete-s · 754 weeks ago

On the good side they did not say 'good' continuous focus. On the other hand they did not say 'crap' continuous focus. But that word does not appear in a marketeer's dictionary.

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Toomas Kadarpik · 754 weeks ago

Nothing compared to A55, it is clear that contrast detect AF does not know the direction to move the lens focus, this is clear visibility, it is like very weak handycam. Sony has it's own issues but overall experience for everyday consumer is very very promising. For predefined studio or location videographing those DSLR-s are of course quite ok, but if you need quickly
to capture something you do not know in advance, the sony is clearly No1.

2 replies · active less than 1 minute ago

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RiceHigh 110p · 754 weeks ago

Not exactly.. All "DV" home-movie cams use CDAF. My NEX uses CDAF. But amongst all of these, the continuous AF during video recording is just quite good to usable.

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radiantlite 29p · 754 weeks ago

I saw the Sony SLT one it is much better.

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radiantlite 29p · 754 weeks ago

it is not continuous AF but it refocuses every time you point into different subject :(

3 replies · active 754 weeks ago

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RiceHigh 110p · 754 weeks ago

And it works just like the "C-AF" of all Pentax DSLRs prior to the K-x! ;-D

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radiantlite 29p · 754 weeks ago

hehe we're cheated again!

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RiceHigh 110p · 754 weeks ago

Not really. All those cameras in all those "C-AF mode" and designs are aimed to search for the focus continuously! So, goal achieved and users are NOT cheated! ;-))

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ART · 754 weeks ago

Actually, D3100 might have sensor made by Renesas (or someone else). It's not Sony's sensor. It looks different; it has different pin-outs, and the effective size of the sensor is smaller (which means the pixel size is clearly smaller, as well -- it works out to 5.1-micron pixels in the 14MP Sony cameras, versus 5.02-micron pixels in the D3100 sensor).

On the other hand, it's pretty clear that the 16MP sensor in the D7000 is a Sony sensor, for all the same reasons it's so clear that the D3100 sensor isn't a Sony: D7000's sensor is listed on the Nikon website and the Imaging-Resource preview as being 15.6mm X 23.6mm, which is just slight larger than the 15.6mm X 23.5mm size specified for most APS-C sensors, including the 16MP Sony sensor in the A55 and the A580. However, this slight difference in size is accounted for by the fact that Nikon is using 16 more columns of pixels in the D7000 implementation, than Sony is using in their own cameras (output resolution of 3264 X 4928 for the D7000, versus 3264 X 4912 in the A55 & A580). So in reality, the pixel size works out to 4.78 microns in all cases.

3 replies · active less than 1 minute ago

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RiceHigh 110p · 754 weeks ago

I haven't heard before Renesas is making any sensor, could you point us to a link to the specs or datasheet online? (I have visited their America mainpage but found nothing.)

Btw, the effective resolution and pixels as well as the sensor "size" have nothing to do with the real physical parameters of a sensor, which can be changed by different design. So, you cannot tell if it is the same sensor or not by just comparing these. Just for example, the camera maker can use more lines of pixels for detecting/calculating the dark current. In more laymen terms, a good example is the Nikon D90/D5000 and Pentax K-x uses the same Sony 12M sensor (as generally believed), but the total effective pixels of the Nikons and Pentax are different, namely, 12.3M Vs 12.4M.

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Oodini · 754 weeks ago

http://digitaljournalofphotography.blogspot.com/2...

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RiceHigh 110p · 754 weeks ago

It says in the beginning that, "Renesas are *rumored* to be the makers of the CMOS imager in the Nikon *D3* and *D700*"..

Firstly, it's just a rumour. Secondly, it mentions about D3 and D700, but not the D3100.

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DED · 754 weeks ago

It's better not to put in camera such kind of AF in video.

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(noou) · 754 weeks ago

the video AF on the d3100 is simply useless and ridiculous

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erwinmul 13p · 753 weeks ago

Focus is an important thing when using DSLR for recording movie. Due the shallow DOF in DSLR, even a little inaccuracy of focusing will make an image totally out of focus. This is why for precise result, we still need a lens with easy and accurate manual focus ring. A contrast detect methode simply unable to keep following such a moving target like that.

1 reply · active 753 weeks ago

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RiceHigh 110p · 753 weeks ago

Yes, for your first statement. But for the rest, my experience is that continuous human manual focusing would do no better, especially when we take videos outdoor under a bright sun! :-(

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Wednesday, September 29, 2010

Does "Continuous AF" under Movie Mode of the Nikon D3100 Work?

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