Is this lens OK? (See picture!)

[billhercus]

Data: Sigma 100-300 f4 EX APO with Sigma 1.4TC on 20D

100-300mm @ 420mm
1/2000 sec, f/6.3
Mode: Av
Metering: Evaluative
ISO: 400
AF mode: One-shot AF
Drive: Single frame shooting

Picture is 100% crop of bird approx 100 metres away from my attic window. Hand held shot. Small amount of post processing in RawShooter and Photoshop.
I am disappointed with the poor detail here. Should I be? Is my aperture too small? BreezeBrowser says it is in focus on the near wing.

Basically, is this what I should expect from a lens of this quality?

Appreciate advice here?

http://www.mayfieldghouse.freeserve.co.uk/Webpics/Pigeon%2005Apr1467-02.jpg

[eastcoast909]

Well, it is not an L series lens but I really think that you are being too hard on it.

If you look at the dynamics of the picture you say you are 100m from the bird. If you assume that the bird is 1.5 ft in lenght (generous assumption) then you would need a lens that is 7034mm big to get a full frame picture on a standard 35mm camera.

Some what smaller on a 20D.

If you check out the last bird pictures by IanD and SSIM you will see that they are no where near 300 feet away from these owls and they are using the BIG L's

Use a tripod, slow down the shutter speed and probably stop down the aperature, however I have not used a setup like this so can't give you further ideas other than that.

[pfuller88]

Picture looks a little dark. More light might help. I also suggest slowing the shutter speed way down, stopping down to 8 or higher and going with ISO 200 or 100. Shooting in AV mode (as you are) to force the AV to 8 or higher. Manual mode will allow you to control the AV & Shutter (watch the guage in the view finder for over or under compensation when in Manual mode and adjust accordingly - you don't want to force the camera to far off the norm to get a clean picture).

Enjoy the new toy!

[RichardtheSane]

I too think the exposure is a problem here. The image is definitly too dark.
Under exposure on a DSLR will cause you to loose detail as the amount of information it is possible for the sensor to record is significantly reduced.

Good reading on the subject, and I think the cause of your poor detail here
http://www.luminous-landscape.com/tutorials/expose-right.shtml

[Cadwell]

The bird looks under exposed to me. Easy to do when you have a small, dark-ish subject against a light background. That coupled with ISO 400 and the fact that you've got a 1.4x teleconvertor in there (which teleconvertor BTW?) so you're running 1/3rd of a stop off of wide open.... Oh, and knowing Forres it's probably blowing half a gale so that branch'll be swaying round like a whip ;)

[CyberDyneSystems]

Anything I can see wrong with this image has nothing to do with the lens.

A lens,. no matter how good,. can only take the pictue that the camera and photographer have it set to take.

You need to get closer,. expose properly,. get white balance,. etc...

[Cadwell]

Well, it is not an L series lens but I really think that you are being too hard on it.

I should add that from my own experience of a good copy of this lens (a friend has one and I've used it), it compares favourably with the EF 100-400L and it's pretty good even when compared to the 70-200mm f/4L.

[MediaMagic]

I think this is a great example of exposure compensation.

On this shot, it looks like an EC of +1 or +1.5 needed to be dialed in. It almost appears to be an extraction. The camera metered this shot and balanced the scene to a dull grey (that's what it does). With an overcast backlight like this, you will have to overexpose (unless you have a spot meter) the settings the camera's meter to get the exposure you really want. It would be tough not to blow out the sky while exposing the bird properly.

The camera meter will get you close, but you have to look at the scene you are shooting and then overexpose to keep bright/white colors bright, or underexpose to keep dark/black colors dark.

Here's a visual example of this shift and exposure compensation I put together some time back.
http://www.mediamagicnw.com/ectest/ec.htm

[Hellashot]

The 1/2000 sec may contribute to the dark image. You should have gone to ISO 100 and used a more normal shutter speed.

[robertwgross]

The 1/2000 sec may contribute to the dark image. You should have gone to ISO 100 and used a more normal shutter speed.

I disagree. As was just stated previously, this is not directly an exposure problem. It is a metering/user error. With a bright backlit sky, something like +1 or +1.5 EC should have been tried. Centerweighted metering pattern would have helped, but the original poster stated that this was a 100% crop. So, it might have been just a dark speck in the center of a bright sky. No wonder. Evaluative metering can't do everything.

---Bob Gross---

[drisley]

First of all, the bird is backlit. Secondly, was this taken THRU your attic window?
If so, this isn't a very good test of your lens since the image can only be as good as glass in front of you. And unless your attic window is made of L glass....

[billhercus]

Thanks for the terrific detailed replies here which are food for a lot of thought. Firstly, there was little movement in the subject however, the picture was not take through the attic window - come on chaps!! I do take the major point about exposure against the sky.I used only the centre auto focus point in Evaluative thinking this would tend to expose more accurately for centred object. Obviously not. What if I had used Partial Metering or Centre Weighted - which would be best here with a really small object against the sky? Is this use of the centre focus point only really effective with f2.8 lenses or am I being confused with something else?

This revised picture below has applied just over 1.5 stops of exposure compensation in Rawshooter. It is better, but note there is no increase in detail and thus is possibly a good example of the benefits of "exposing to the right" where better detail would have come out?

Assuming everything else the same, why would a reduction of shutter speed, on its own, improve detail?

It's great to know its me and not the lens - I can easily change at no cost!!

The learning cuvre steepens ......

http://www.mayfieldghouse.freeserve.co.uk/Webpics/Pigeon%2005Apr1459-02.jpg

[MediaMagic]

Heya billhercus,
I think you just need a little practice with this lens. You'll never be able to make a decision based on a single hand held shot. There are a few factors to consider here:

In this picture, you have the lens zoomed to 300mm, at f6.3. I would guess (and this is only a guess based on the characteristics of most zooms) that this lens is going to perform its best at 200mm/f8-f11 (the sweet spot). If you are all the way out at 300mm, you might lose a hair or two of sharpness/minute detail. When you add a converter, you might lose another hair of detail. By being wider than the lens' sweet spot, you again lose an eyelash of crisp detail. If you bump up the ISO to 400 you may lose another eyelash of detail. If your shot is underexposed, you'll probably lose a little detail. Okay, so that's where you are before you ever squeeze the shutter, about 3 hairs and and a couple of eyelashes down from optimal performance.

Now the scene itself.. Looking at the 100% crop, you have a tiny greyish bird, on a bright grey backlit background. This is a very tough condition to get both a good pinpoint focus and proper exposure (a small error in either of those will decrease crisp detail).

If I were to shoot the exact scene with my 100-400L zoomed to 400 with a 1.4 TC, using your exact camera settings, I expect that the level of detail would be roughly similar though the bird would be slightly larger in the frame.

You will need to take quite a number of very controlled shots to see the actual detail the lens/TC combo is truly capable of. There's no way to get that from one 'off the cuff' shot. And, as always, the more you practice with the combo, the more detail will magically begin to appear in your shots.

[Cadwell]

This revised picture below has applied just over 1.5 stops of exposure compensation in Rawshooter. It is better, but note there is no increase in detail and thus is possibly a good example of the benefits of "exposing to the right" where better detail would have come out?

Digital exposure compensation is useful but it can't bring out detail that wasn't recorded in the first place due to under-exposure, so yes, exposing to the right helps.

[gulogulo1970]

Get closer next time.

I kind of like it. It reminds me of a watercolor.

[poke]

The 1/2000 sec may contribute to the dark image. You should have gone to ISO 100 and used a more normal shutter speed.

I don't see how a high shutter speed will contribute to a dark image. As I understood it, the shutter and aperture work in tandem to let light through to the sensor. If you have 1/2000 with f6.3 then the same result would be returned if you adjust each an equal amount of stops... now I haven't done the calculation, so the eact figures here won't be right but if it were to be something like 1/250 with f22 then theoretically the same amount of light should be reaching the sensor... ie exposure should be the same, only the depth of field will be greater, and object movement will be more pronounced.

[lostdoggy]

I've been using a Sigma 28-300 lenses for the pass several month and have been very satisfied. Being that I can't afford a true L/IS lenses I have to be satisfied and you should too if you haven't save up enough for a L/IS lenses.

[Andy_T]

Lostdoggy,

it might be different if you pay 900$ for the Sigma 100-300/4.0.

I think the picture is not that bad given the enlargement and wrong exposure.

I think it suffers from purple fringing (no big surprise for a backlit tree picture) and we do not know what amount of sharpening was applied.

Best regards,
Andy

[billhercus]

A very useful set of replies here, as always in this forum. MediaMagic's reply in particular I think summed up the whole problem beautifully and for that a special thank you! :D When I next take a similar pic they will be incorporated. If I catch another pigeon there - I''l publish!

In summary:
1. I have enough info (on just one shot I know) to feel happy with the lens
2. Small objects against a bright sky - 'expose to the right' i.e., about +1.5 EC
3. If you can - go for the sweet spot maybe f8-f11 region
4. Use ISO 100-200 (if you can hand held, etc)

Not convinced:

1. Slower shutter speed

Thanks guys!!