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Question about 100-400mm IS Canon lens – EOS 20D and RAW… claudine Gold Star Critiquer [C: 2486 W: 0 N: 0] (0)::2006-12-05 21:07
Hello,
I really wonder something : I use Canon 20-D and recently I started shooting in RAW. I set my camera on “RAW capture only” and it seems that my 100-400 mm IS Canon zoom become a little slower on automatic focus. Most of the time I set my camera at manual settings but except for the focus…

Do I mis something here or is it just normal as RAW files are heavier and slower camearas?

Thanks in advance for answers,

Claudine
Re: 100-400mm IS Canon lens – EOS 20D and RAW… SunToucher Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 2385 W: 237 N: 3033] (11162)::2006-12-06 2:21
Hi Claudine,
I have no idea, but I am going to follow this thread with interest. Since I am interested in the lens. I've never experienced any delays in my camera or lenses when shooting in RAW.

Niek
Re: 100-400mm IS Canon lens – EOS 20D and RAW… sAner Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1455 W: 74 N: 1426] (4750)::2006-12-06 2:50
Hi Claudine,

I have a canon 350D and own a Sigma zoom lens (100-300 APO) and a Canon zoom lens (70-200 L) and I shoot in RAW. Like Niek I have never experienced slower focussing when compared to shooting in jpeg.

Regards,
Pieter
Re: Question about 100-400mm IS Canon lens – EOS 20D and RAW CaptiveLight Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 435 W: 61 N: 232] (969)::2006-12-06 2:57
I use my Canon 20D with the Canon 100 - 400 L an awful lot, and I can't see any difference in AF speeds when using RAW compared to Jpeg. Mind you I almost never use Jpeg...

The only difference you should really notice is a slow down when firing bursts of images once the buffer is full.
Re: Question about 100-400mm IS Canon lens – EOS 20D and RAW JeanMichel Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 633 W: 87 N: 938] (2864)::2006-12-06 4:43
Bonjour Claudine,
I use a 20D,many times with the 100-400L IS. I never noticed any change in AF speed wether I shoot Raw or JPEG. In fact, the choice between these two image filing procedures should only affect the speed of recording on your camera buffer (internal memory) before transferring it to your CF card. That is why, when you shoot in burst mode, the number of consecutive images your buffer can accept is less in Raw(heavier files) than in JPEG(lighter files), and you can't shoot while your camera is busy to transfer from the buffer to the CF card.
The autofocus speed is independant and should not be affected by the filing system you choose.
J'espère que c'est clair, sinon je vous l'explique en français plus tard.
Cordialement
Jean-Michel
Re: 100-400mm IS Canon lens – EOS 20D and RAW… livios Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 2150 W: 319 N: 4263] (16942)::2006-12-06 20:00
Claudine, I use the 20D and the 100-400 by Canon. Even though, autofocus works well with the gear.

As others have already mentioned, some difference can be noticed when firing bursts.

Best regards.

Lívio
Re: 100-400mm IS Canon lens – EOS 20D and RAW… claudine Gold Star Critiquer [C: 2486 W: 0 N: 0] (0)::2006-12-07 5:48
Thanks for your answers everybody. I lived this situation mostly while shooting Black-capped Chickadees that are very fast moving birds and I shot many these times so, it might not be due to the RAW format but most to these subjects I chose ;)
Claudine
Re: 100-400mm IS Canon lens – EOS 20D and RAW… Aramok Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 896 W: 101 N: 1501] (5166)::2006-12-15 2:47
I've not been around for a while, so sorry for the delay.

Even when the camera is set to jpeg the camera always records in RAW and then converts the file to jpeg as it writes it to the flash card, so if anything it should be quicker in RAW only. The camera uses a set filter to convert to jpeg which never varies for the conditions etc, so it is better to shoot in RAW and manually control the filters afterwards.

Similarly with B&W, RAW still records in colour (I found this out in the summer when I played wit settings on holiday and at the conversion stage in Canon's DPP (or any other raw converter software) you can set any B&W photos back to colour without any losses...)

So in answer to your question, as with the other, I don't think it is the camera... maybe you have enabled another setting my accident along the way. The camera does have an automatic DOF option, which would take longer, but you set you manually set those filds.

Maybe you need to look at the settings for where you focus from. I have mine set to the center (left, middle or right) points most of the time because I have noticed that my camera and my lens combination does not focus as easily on the top or the bottom focus points for some reason. I'm waiting for my 2 new lenses to see if this is feature or just the orginal lens I was using. But I tend to stick with the middle center focus point which is much faster for some reasona and then holding the shutter release down, adjust the composition and the take the picture. Perhaps this is what you are notcing - but with the next step up camera (I'm on the 350D), I would be surprised if this was an issue, but maybe it is...

Hope that helps

Emma
Re: Question about 100-400mm IS Canon lens Steve Silver Note Writer [C: 0 W: 0 N: 43] (338)::2006-12-15 5:48
RAW files are larger than jpeg files and so they will fill up the camera buffer sooner and take a little longer to write to the momory card than the jpeg files. I use the 20D and 30D with the 100-400 and have not notice any difference in focus speed when I used Raw or jpeg files.
Re: buffer vanderschelden Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 2553 W: 74 N: 7464] (30441)::2006-12-15 10:38
And for the latter the main reason this happens is the RAW file's size; as this is pure data; no compression.
Re: 100-400mm IS Canon lens – EOS 20D and RAW… claudine Gold Star Critiquer [C: 2486 W: 0 N: 0] (0)::2006-12-18 14:30
Thanks Emma for those very interesting informations :-)
Claudine
Re: Question about 100-400mm IS Canon lens marhowie Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 5731 W: 1197 N: 98] (486)::2007-02-24 0:47
Claudine.
I read the ? had a hard time understanding what the ? was :)
Raw capture as opposed to JPEG has NOTHING to do to with AF, but everything to do with the number of images you can pull down when shooting in continuous or high speed mode.
The only factor that will affect the AF speed will be: the available light, the length your are "zoomed" and the limiter (distance) setting on the lense..
OK ;}
Howard
Re: Question about 100-400mm IS Canon lens mogens-j Gold Star Critiquer/Gold Star Workshop Editor [C: 751 W: 128 N: 5] (20)::2007-02-24 9:21
Hello Claudine

Contrary to many other camera manufactures Canon has placed the focus motor in the lens instead of the camera house. This means that every Canon lens has its own focus motor which fits exactly to the specific lens. Just for that reason the file format can never have any influence at all on the focus speed. The reason of a slower AF could be that the target is difficult to get in focus etc. a target with very dark colours like a Blackbird or a clean white surface. Also poor light conditions can make it slower. The AF focus by looking at the difference in dark and bright areas. Let me give you two extreme examples:

1. On a Tiger in bright daylight the AF will work fast because of the contrasts.
2. On a Dark subject in poor light the AF will work very slow (or not at all) because of missing contrasts.

Hope it is at any help.
Mogens
Re: Question about 100-400mm IS Canon lens – EOS 20D and RAW bobair Gold Star Critiquer [C: 400 W: 128 N: 1] (44)::2007-02-26 21:44
Hi Claudine,
have you checked your camera's firmware version and then gone to the Canon website to see if there are any issues with it and a possible update version.Another thing that can slow you down is the type of CF card you use,the higher the write speed the more quickly you can get your shots,this I'm sure you probably know already but thought I would mention for the sake of newbies to digital SLRs.I hope I was of some assistance. Bob