sigma 70-300 apo. not really sharp.

fguihen

i have a sigma 70-300 apo. i got it as i needed a long focal length for wildlife photography. the problem is i cant get any super tack sharp images. in fairness it was only 170 quid.

my old panasonic bridge camera had an equivalent lens and although it had its down sides, it was really sharp.

likewise the old camera was class for macro when attaching a Nikon 4T and /or 5T. when trying a similar setup with the 70-300 sigma, the DOF is even less than on the old panasonic and so much more difficult to get good images.

would it be best to struggle on and try to get more from this lens or am i using it at its limit and would be better to spring for a decent 70-300 zoom and the infamous 100mm canon macro lens?

bp_me

Care to show us some where it's not sharp? You're not shooting it wide open I presume?

amcinroy

fguihen,

I am also using this lens. While it's not as sharp at the wide end as my Pentax 70mm DA prime, it is a very repectable performer and most reviews of this lens are positive. I find personally find it to be very good up to 200mm and reasonable at 300mm.

Are you sure that you are using a high enough shutter speed?

At 300mm you really need to be using 1/500th of a second
at 70mm you should probably be using at least 1/180th

A good braced position may also help. You can't beat a tripod though.

Andy

Ninja_scrotum

I have this lens too. I wasn't expecting tack-sharpness cos I only payed 120e for it, what do you expect like!

But there is an annoying slight blueish haze in most of the photos I've taken with it. Anyone know what that could be? Anyone have the same problem? It's not my camera because I've searched flickr for images taken with the 70-300 and a lot of them have that blueish tint too...

mike65

No zoom is going to match a fixed lens and the greater the difference the more lenses, every piece of glass and the mechanism to move it is a potential weakness in the optics chain.



Mike.

fguihen

il try to dig out some examples later on. the problem is that at full zoom ( needed for most birds) the smallest apature is 5.6. this means you are usually quite underexposed at 1/500. likewise with macro, the DOF is a bit better up around F18, but likewise, each image takes takes like half a second to obtain the correct exposure, and creepie crawlies usually have moved by then, and also, when using macro you are at the 300mm end and so would need a speed of 1/500. cant be remedied with a flash either as their max speed for the 400d is 1/200 of a sec i think.

i got a monopod to try to help illeviate my arm shake, but it hasnt helped much so far.

DaireQuinlan

Ninja_scrotum wrote: »

But there is an annoying slight blueish haze in most of the photos I've taken with it. Anyone know what that could be? Anyone have the same problem? It's not my camera because I've searched flickr for images taken with the 70-300 and a lot of them have that blueish tint too...

Do you use a lens hood ? Telephotos can be particularly prone to flare, as its sometimes not immediately obvious that bright light sources (ie, the sun) are casting light across the front element of the lens. If you have a lens hood always clip it on :pac:

Other than that, not a clue. Some lenses reportedly have warming or cooling effects on a picture, but nothing so serious as could be described as an actual noticeable bluish tint.

amcinroy

You could try pushing the ISO up a bit. A sharp ISO800 image is preferable to a soft ISO100 one. This will allow you to use a faster shutter. Now you can see why bird photographers like large aperture lenses.

I like a macro expert guide you on the other points.

DaireQuinlan

fguihen wrote: »

il try to dig out some examples later on. the problem is that at full zoom ( needed for most birds) the smallest apature is 5.6. this means you are usually quite underexposed at 1/500.

What's your ISO set to (presuming you're using digital here, if not then replace with 'what ASA film are you using :pac: ) ? I have a similar Nikon lens, 5.6 at the long end. In bright sunshine at 5.6 and with the camera set to ISO 100 you'll get a good exposure at 1/800th of a second. Overcast days you'll lose a stop so you're down around the 1/400 mark. Anything dimmer than that and you're in tripod/monopod territory. I actually very rarely use mine for this very reason. Its good handheld on sunny days, but its a writeoff for handheld work in any other conditions at 300.

-edit-

should have mentioned, I shoot a lot of slow (50/100) slide so upping the ASA isn't often an option for me. I've taken some good stuff with portra 800asa on cloudy evenings though, handheld and carefully braced, most of this set was taken around the 300 mark:
http://www.flickr.com/photos/dairequinlan/sets/72157601830662194/

-edit-

amcinroy

And I might be cheeky to point out that this is a great selling point for in-body stabilisation.

Thankfully my Sigma 70-300mm APO is stabilised.

Pentax anyone?

fguihen

What's your ISO set to (presuming you're using digital here, if not then replace with 'what ASA film are you using ) ? I have a similar Nikon lens, 5.6 at the long end. In bright sunshine at 5.6 and with the camera set to ISO 100 you'll get a good exposure at 1/800th of a second. Overcast days you'll lose a stop so you're down around the 1/400 mark. Anything dimmer than that and you're in tripod/monopod territory. I actually very rarely use mine for this very reason. Its good handheld on sunny days, but its a writeoff for handheld work in any other conditions at 300.

my ISO is generally at 100, but i have pushed it up to 400 on occasion. i try to avoid this if possible at all. as to your other points, your nikon performs pretty much like my sigma. unfortunately i enjoy mostly macro and wildlife photography which was my main reason for getting the lens.

snellers

I know some people will frown upon this fact but don;t forget that as long as you don;t blow the highlights and have a reasonable histogram you should be able to recover the picture - so try and use the optimum shutter speed with tripod/monopod and see how that goes. (if using tripod try and get a shutter release unit and make sure it is in shutter up position (reducing camera vibration) - if no shutter release cable then at least put the camera on timer - this really can make a lot of difference

Anouilh

Using a tripod helps a lot and I am very pleased with this lens.

Also, working with rather against the lens somehow works in manual.
Some flowers and grasses can be enhanced and softened,
which makes them more textured and somehow more alive.

Some over sharp photos can be very harsh.
When photographing animals, softening the fur
can make it look less that the animal has its
hair on end from stress.

Just some personal reactions...

AnimalRights

amcinroy wrote: »

Are you sure that you are using a high enough shutter speed?

At 300mm you really need to be using 1/500th of a second
at 70mm you should probably be using at least 1/180th


Andy

HI, question, I'm at the stage where I'm learning the shutter speed and I read what I assumed was for focal length the shutter speed had to be a little more...
500 is a lot more than 300?
and 180 is a lot more than 70??
Is it because a Sigma is naturally a darker lens then a Canon lense? the 1 Sigma lense I owned 28-200 was so dark I needed a miracle to see anything!

fguihen

HI, question, I'm at the stage where I'm learning the shutter speed and I read what I assumed was for focal length the shutter speed had to be a little more...
500 is a lot more than 300?
and 180 is a lot more than 70??
Is it because a Sigma is naturally a darker lens then a Canon lense? the 1 Sigma lense I owned 28-200 was so dark I needed a miracle to see anything!

the general rule of thumb is to use use a shutter time thats smaller than the focal length your using, so for a 300mm focal length, on a 1.6X crop camera like the 400d, the focal length becomes something like 480mm i think, so the 1/500 is the closest shutter speed to that.

you sure your shooting with the apature is wide open?

amcinroy

Animal,

Yes, you need to factor in the sensor crop when you are using that rule.

The rule also starts to break down towards the wide angle.

For instance, I would never dream about using my 14mm at 1/14th or even at the 1.5x crop equivalent of 1/20th.

Andy

AnimalRights

Cheers, just I had to ask, I know you have to take other things into consideration too also!

Anouilh

Ninja_scrotum wrote: »

I have this lens too. I wasn't expecting tack-sharpness cos I only payed 120e for it, what do you expect like!

But there is an annoying slight blueish haze in most of the photos I've taken with it. Anyone know what that could be? Anyone have the same problem? It's not my camera because I've searched flickr for images taken with the 70-300 and a lot of them have that blueish tint too...

Did you change the in-camera picture style settings at some time and forget to change them back? (Though I know you say it is not the camera.)

As usual, seeing an example might help, if you would like to upload a typica photo that is not correct.

JMcL

fguihen wrote: »

il try to dig out some examples later on. the problem is that at full zoom ( needed for most birds) the smallest apature is 5.6. this means you are usually quite underexposed at 1/500. likewise with macro, the DOF is a bit better up around F18, but likewise, each image takes takes like half a second to obtain the correct exposure, and creepie crawlies usually have moved by then, and also, when using macro you are at the 300mm end and so would need a speed of 1/500. cant be remedied with a flash either as their max speed for the 400d is 1/200 of a sec i think.

If you're shooting wide open at 300mm, then the lens will be a bit soft. I have it as well, and it's an excellent performer up to 200mm, or even a bit more, but it is soft fully zoomed. Stepping down to f8 or f11 helps, but it doesn't help your speed problem.

For your macros, if you're looking at exposures of 1/2 a second, and to get the DOF at 300mm you do need to stop down, you really need a tripod. Alternatively, practice with your monopod and get your flash out if you want to chase bugs. You should have easily enough stability on a monopod to shoot at 1/200s.

Anouilh

Overall this lens has had very good reviews.
I would be interested in knowing how you resolve the colour cast problem.
Setting the in-camera style to "Landscape" mode could cause this, or so I've read by looking at various Canon sites.
Also using automatic White Balance can cause unwanted colour casts.


I shoot in RAW and can change the white balance afterwards.


There is a lot of help available on the Flickr lens sites.http://www.flickr.com/groups/400d/discuss/72157605278700242/