300 f/4 IS + X1.4 Focus speed

[tal_sarih]

<p>I know this question has been asked a thouzand times BUT...<br>

Can someone, please, who has a 300 f/4 IS post a focusing speed test on youtube and provide a link? I can't find anything like that, anywhere. And if you have the x1.4 extender, please attach it and post that too.<br />Also, does the x1.4 reduce quallity THAT much that the lenses same quallity as the 100-400? </p>

[bobatkins]

<p>It slows it down a bit, that's all you really need to know. It's still quite fast. The image quality drops a bit, but not THAT much.</p>

[eric merrill]

<p>Are you trying to compare it to another lens?</p>

<p>What do you want to know? By itself, it has an acceptable focus speed. I wouldn't use the phrase quite fast, but it's not slow, either. With an extender, the focus speed is reduced. If I recall correctly, 1.4x extenders increase the focus time by a factor of two. You can overcome this by taping certain pins, but then you'll lose accuracy.</p>

<p>If you're looking for fast focusing speed at that range, the 400/5.6 is going to be about twice as fast as the 300/4 + 1.4x.</p>

<p>Eric</p>

[pto189]

<p>In one thread posted previously on this forum, you said you have $750 to spend and asked what gear you should buy. In another thread on Nikon forum, you listed 15 reasons to upgrade to Nikon D7000 and said you hate keeping Canon gears. Now you are asking the Canon 300 f/4 IS + 1.4x TC focus speed. Are you planning to switch to Nikon or to buy the Canon 300 f/4 IS + 1.4x TC?</p>

[zafar1]

<p>Like Bob said, you take a hit in AF speed with using 1,4x but it depends. I would rate the sharpness same or better than 100-400 @400. However the AF is noticeably more hesitant, specially on my 5D Mk II.</p>

<p> </p>

[lester_wareham]

+1 to bob, it is my only birding lens and I can get very sharp images from 1/4 of a 7D frame with this combo, also good for

BIF. I am sure the 400/5.6 is better, but by how much?

[pjmeade]

<p>I've used the 300/4 IS to photograph equestrian sports, cricket and birds. All of those can be quite demanding, but the 300/4 with or without the 1.4x keeps up. Except perhaps trying to get a kingfisher in flight, but that's probably my reactions.<br /> Having the focus range set to 1.5 m will make a major difference to focus speed for longer distances.<br /> <a title="At the races - Also ran by Peter Meade, on Flickr" href=" src="http://farm1.staticflickr.com/180/439052540_18187e0d40_m.jpg" alt="At the races - Also ran" width="240" height="160" /></a><br /> <a title="Iain O'Brien bowling action by Peter Meade, on Flickr" href=" src="http://farm5.staticflickr.com/4083/5080560055_719c2547d0_m.jpg" alt="Iain O'Brien bowling action" width="240" height="40" /></a></p>

[tien_pham]

<p>1. Depends on when you shoot. Low or high contrasty time/subject is harder for focusing.</p>

<p>2. Depends on what type of body you have, A 300mm f/4L + 1.4TC would have f/5.6 as the max aperture. Depending on the body, this aperture may be too small for focusing. Thus focusing would be slow. For example, it is not a wise idea to go 100-400mm with a 1.4TC. When you're at the long end and your body is 50D, your camera cannot make a focus!</p>

<p>3. Depends on which type of focus sensor is. A cross type sensor is better for focusing.</p>

[craig_meddaugh]

<p>Measuring focus speed scientifically is just about impossible without going through a lot of hoops as here is a brief list of some of the things that you would have to control for:</p>

<ul>

<li>Scene EV</li>

<li>Subject contrast</li>

<li>Subject distance</li>

<li>Subject/background distance and contrast differential</li>

<li>Subject movement </li>

<li>Camera body and the specific AF point</li>

<li>The current focus distance of the lens</li>

<li>How the limiters have been set</li>

</ul>

<p>Absent doing all of that, you can either simply time how long a lens takes to rack from near to far, which has just about no relevance to real-world shooting or you can rely on subjective experiences of others. </p>

<p>So here is my two cents worth. 300/4 sans extender: Slightly sharper than the 100-400 and slightly faster to acquire a subject. 300/4 with Canon extender (II or III): Not as sharp as the 100-400 and slightly slower to acquire a subject. However, the differences are so small as to not have any real-world relevance. </p>

[philip_wilson]

<p>Agree with Bob. In my case I find the AF is fine with the 1.4x and have shot ski racing this way with no problems. Birds in flight are more difficult but still usually works.</p>

[w_t1]

<p>I also agree with Bob. I use mine almost every weekend 300f4is with and w/0 the 1.4 to shoot soccer and other sports.</p>

<p>There are plenty of analysis guys over at that other site that would love to run your test for you, though...</p>