400d Struggles in Low Light

<p>I have a 400d and a 50mm f1.8 and struggle to get sharp pictures indoors without a flash. I will get a new lens but was also wondering if a new body, such as a 40d would help (the price is quite good at the moment with the 50d out).<br>

I will probably get a Tamron 17-50 f2.8 as my kit lens broke but do you think that in order to get sharper indoor shots I will have to get a better prime as well or a new body?</p>

<p>Yes, 40D AF is much better in low light (plus the VF is much larger & brighter). The 400D only has a single cross sensor (center one is senstive to both to vertical and horizonal lines) while the remaining 8 are single axis only. The 40D is more sensitive in low light and has 9 cross sensors. You get a lot fewer misses. However, I suspect the main problem is your EF 50 1.8. Although it yields a bright VF, its AF performance in low light among the worse in the Canon lens lineup. Mine constantly racked back 'n forth in such situations. Terrible. Even a slow zoom like the EF 28-105 3.5-4.5 USM runs circles around it in low light. The combination of ring-type USM, rear element focus makes a massive diff in AF performance.<br /> <br /> I don't own the Tammy 17-50 but I did try it in the shop. AF was really slow, noisy and jumpy in low light. It is better than the EF 50 1.8 but a long ways from a Canon ring-type USM design. The worse part was the MF ring spun wildly during AF, so watch your fingers. I guess they omitted a crutch mechanism to save a few pesos.<br>

<br /> Incidentally, I love your movies. Kickass stuff!</p>

<p>The AF of the 40D is of course better than that of the XTi/400D, but even with my 40D the 50 f/1.8 still hunts. The AF of the 50 f/1.8 is not the greatest.</p>

<p>I wouldn't have expected the lens to factor that much into low light autofocus except for the aperture size, f1.8 is about as good as it gets. Tell me if I'm wrong, I just don't see how it would affect it further. The motor is louder and slower than most so maybe it is just more obvious that the camera is struggling and the hunt for focus is slower.<br>

The 40D would be much better in low light, it does have more cross sensors but the real advantage is the second centre point sensor that is much more sensitive when using lenses faster than f2.8. You also have a better chance with manual focus since the viewfinder is brighter and you can buy a replacement focus screen that is designed to aid manual focus.<br>

The most likely reason for unsharp pictures though is not the autofocus itself but the slow shutter speed and the small depth of field with fast lenses but again the 40D would help since you can use a higher ISO setting and the autofocus will hopefully be more accurate so the depth of field will be where you want it.<br>

I do a lot of low light pictures with my 40D, i'd go full frame if I could afford it just for this reason. Every camera has it's limits and I've happily watched my 40D and 50mm f1.4 struggle and fail to get the shot I wanted just because the light wasn't there. A 400D is a fine camera and you have a fine lens so just be sure you can burn the money on something that is better but not necessarily that much better.<br>

A small tripod might be the only thing you need for sharp pictures and far more cost effective. You may find you buy a 40D and get exactly the same results because it is the situation you are shooting in and not the camera itself that limits you.</p>

<p>I have the 400d and AF in lowlight isn't great. (Manual focus is possible but you might miss a few shots so shoot multiple pictures.)</p>

<p>Buying another body might be an option but remember that any combo falls apart when it gets dark enough. I really wonder if the 40D would be much of an improvement. (A second hand 5D or a new 50D might be better in low light.)</p>

<p>Another thing to consider is that at very wide apertures your depth of field is very shallow so the pictures may be bad because of that.</p>

<p>I recently bought the EF 50/1.4 and it does perform a little better. (And it's a lot cheaper than a new body...)</p>

<p>Kind regards, Matthijs.</p>

<p>Form what the OP writes, it is unclear if the problem is AF or if the problem is long exposure times (due to ISO 100 for example). ... Please post a downsized example (with intact EXIF data) that shows the problem.</p>

<p><strong>What Rainer said</strong> .<br>

There's <em>no way</em> that sensible recommendations can be made without some indication of what the actual problem is...</p>