kasperhettinga

<p>I've owned at least 10 sigma & tokina lenses over the last years and really none of them showed focussing problems. Only lens with problems I've ever owned was a canon 28-90 kit lens: focussing had always been a hit&miss and after 3 years AF stopped completely.<br>

Only thing I don't like with some older Sigma lenses is incompatability with newer bodies...</p>

<p>This tamron lens is the cheapest 70-300 lens...both in price and quality...</p>

<p>:D</p>

<p>At 11mm&f/4, the hyporfocal distance is indeed about 5ft, thus when focussing at/beyond this point, infinity should be sharp...<br>

Only thing I can think of it that it focussed, wrongly, very close.</p>

<p>My sigma 10-20mm at 10mm (f/4) hardly gives OOF areas in this type of shots: only when I focus very close to the camera infinity looks OOF or when I focus further away, something very close to the lens looks OOF.</p>

<p>Advantage of the wide angle is that you don't need to stop down much to get a hugh DOF..<br>

http://www.dofmaster.com/dofjs.html</p>

<p>28-300L is only quality lens in this range, but whether it will make you happy? I would suggest 2 lenses for this range ...</p>

<p>Or you can make a standard develop setting, which you apply automatically to all imported photos (e.g., if you sharpen all pics to a certain level and increase contrast to a certain level, then you can make a develop setting which only applies these two settings and leaves the rest of the settings alone).</p>

<p>I don't know about this specific lens, but in general, if the point you focus on is beyond the hyperfocal distance, the lens could simply be set to the hyporfocal distance and be within specifications: the point you focus on is within the DOF, so the lens is set OK.</p>

<p>First and most important question I would say: are the pictures in focus?</p>

<p>With wide angle lenses, I've seen the same effect. This doesn't hurt the picture, due to the hyperfocal distance being very close. At the hyperfocal distance, every from that distance until infinity is in focus (and also some in front of this distance.<br>

You can do some test calculations overhere:<br>

http://www.dofmaster.com/dofjs.html<br>

24mm&f/4 on a 5D give a hyperfocal distance of about 5m/15ft</p>

 

<p>I was having similar thoughts lately: I'm not looking to replace my zooms, but at adding primes, mainly for my indoor shooting.</p>

<p>As I will stay on crop bodies, a 30 (I'm looking at the crop-only sigma prime), 50 and 85 mm prime would be a nice versatile set of primes to add to the collection. I'm just doubting the 85mm, as I use my (tokina) 100mm macro for outdoor portaits and the 50mm for indoor portaits. Don't know whether the 85mm will thus be used (it's main advantage would be AF speed).</p>

<p>But if you bounce...the light doesn't need to be concentrated according to your lens' focal length anymore...thus the flash goes to a fixed position.</p>

<p>Guy's conclusions that it would be a software option if it would be a digital step only is not correct I think. If e.g. ISO 50 would indeed be a 50% reduction of the ISO 100 signal, it would have to start with an EC+1 step, to end up with a correct end exposure, thus involving a step at the shot itself already. Same, but the other way round for H1/H2.<br /> This would also explain the reduction in highlight sensitivity at ISO 50: starting at EC+1 would mean one stop less headroom/tolerance before the highlights would bleach out.<br>

This would be easy to test:<br /> For ISO 50, take a picture at ISO 50 and at ISO 100, but take the ISO 100 picture with EC+1. Then reduce the exposure on your pc with 1 stop for the ISO 100 picture. If the pictures are identical, this is proof for the hypothesis that it is a software-only step.<br /> Off course, it can be done the same way for H1/H2, but then using EC-1/-2.</p>

I've had similar problems if the connector was not seated 100% correct, but just a few millimeter out.

The sigma 10-20 does not work on a FF body.

If looking for a zoom, sigma makes two lenses working on FF: 12-24 ULTRA-wide and a 15-30.

<p>I actually have a center pinch style cap with my sigma 10-20mm (in the box)...bought ik HK. I also want to get this type of cap for all my lenses, much easier to work with indeed!</p>

<p>Alan, now my mistake indeed. I since have set Av to not set shutter to a fixed 1/250, but go to M for flash photography.<br>

Dan, the reason I used this fixed shutter speed was ease of use: when started using flash, I only used 1/250 anyway, so in Av I could change aperture according to DOF-need and not worry about shutter speed.<br>

Now that I also start using fill flash and want more control over ambient light, I stopped using it.</p>

<p>For my <strong>20D </strong> body<br>

Keepers:<br /> sigma 10-20 f/4-5.6 (although faster would be nice)<br /> canon 50 f/1.8 (although a mk II->mk I would be nice or replacement by sigma 50 f/1.4 even better)<br /> tokina 100 f/2.8 macro<br>

New ones:<br /> Sigma 30 f/1.4<br /> Canon 85 f/1.8<br /> Canon 70-200 f/4 (and if santa is nice a 1.4 extender)<br>

Zooms for extremes of my range and 3 primes & 1 macro for middle range.</p>

<p>I recently had some problems with the fixed 1/250. I was using f/8 on a sunny day and without flash it used 1/1000' and with flash 1/250': pictures were quite a bit overexposed (just found out at home, don't use the LCD for checking every pic during a shoot). Luckily only 10/250 were with flash. I learned my lesson :)</p>

<p>1-series body will AF up to f/8</p>

<p>Although I agree that buying crap lenses is no good, these lenses are not crap I would say!<br>

I used the tamron 28-75mm for some time and was really very happy with it...<br>

If you want to compare some lenses <a title="Photozone" href="http://www.photozone.de/canon-eos" title="Photozone">Photozone</a> <a title="Photozone" href="http://www.photozone.de/canon-eos" title="Photozone"></a> is a nice place to start...</p>

<p>IQ/noise has really <strong>nothing</strong> to do with type of CF card...probably the pictures made were not equal in other ways...</p>

<p>90mm = min shutter speed of 1/(90*1,6)=1/144 sec<br>

IS is max 3 stops for this lens (own experience) = 1/18sec</p>

<p>1/4 is about 2 stops more...that's too much. At 4 stops slower (with IS) I have a 10-20% OK rate...never tried 5 stops.</p>

<p>Almost all software (even DPP) will work on vista-64, only the 10D driver not. So just use a card reader in stead of a direct usb connection, and the rest works fine...</p>

<p>I used the 17-70 and is a very nice lens: good IQ, light weight, relatively compact, fast enough for most things and good close-ups...nice lens to start with I would say.</p>

<p>The 28-135 has an effective focal length which reduces very dramatically when focussing closer (at Min. Focus Dis. with lens set at 135mm, the effective focal length is between 60 and 70mm!).</p>