Sigma issues

[Chris Hammond]

I'm using a Sigma 50/500mm APO EX lens on my Nikon D200. I've noticed that my pictures never seem to be as pin sharp as other Sigma users. For instance Graham's (Gslammy) photographs seem to be incredibly sharp.

Even when using my rock solid Manfrotto tripod and setting the camera to Self-timer facility my pictures just don't seem as crisp as other togs on here.

I originally bought the lens to accompany my Nikon F100 film camera, so it isn't a dedicated digital lens. I remember reading that there are some slight technical issues with using older lenses on a digital body. Is it possible that this has a bearing on the lenses sharpness? If not can anybody explain what the shortcomings are likely to be when using an older type lens on a new digital camera?

I'm woefully weak on technical stuff, so please keep any advice as simple as possible. Thanks in advance.

Regards Chris

[RobSutton]

Have you tried it on manual focus?

I had a problem with a Sigma lens that appeared to focus in front of the the object. It was only an issue on auto-focus when I focussed manually it was spot on. I tested it by setting the camera and lens up to photograph a row of books but lined it up so the row of books was at an angle to the camera. I selected the middle auto-focus spot and made a note of the middle title in the row. What I found was that the book in question was not sharp but one slightly in-front was pin sharp. When I focussed manually the central book was pin sharp.

[DavyG]

Hi Chris,

It may be worth posting a couple of examples of your pics which you feel aren't as sharp as you'd like.

Posting the exif details and whether the pics were taken in jpeg or raw would also help, if taken in jpeg please include any in camera settings used.

I agree that Graham's images are very sharp and having seen him in action he has excellent technique!

I'm not sure what post processing you carry out but I find that pp often gives an image the pop that it may not have had straight out of the camera, details of your workflow would help.

Dave

[GME]

I'm sure graham has also said he doesn't like to go below f8 with it either as it isn't that sharp wide open. Try stopping down a bit and see if that makes any difference. It'll limit your shutter speeds though unless you've got good light. Also, you might want to check out the recent thread on long lens technique to help prevent some vibrations that might be present even with shutter release and a tripod. As DavyG suggests - post a couple of examples and let the Bigma experts take a look

[glsammy]

I'd also like to see some images so we can compare. It's right I don't like to go much below F8 if at all possible, at least at the full 500mm. If you back off a bit, to around 420mm, then you can go further and get better detail.
I also do a lot of post processing, if your not doing this, this could well be the reason your seeing such a difference.
I don't think it's anything to do with it being an earlier version. I've seen images taken with earlier versions on a modern digital that easily stand any comparison with any I've taken.

[ChasCreek]

Im no expert but I have been in the past quite frustrated with my Bigma.

Lately I also don't go below F8, I also tend to avoid the 500mm end and don't really go above 400mm with it. The frustration can be having to pump the ISO up to get a decent shutter speed which then degrades the image. One thing I have been doing lately is setting my aparture and then underexposing slightly to give me a faster shutter speed rather than pumping up the ISO and then fixing this afterwards in CS3. My images have improved but in 'normal' and not very bright light conditions I am always doing a lot of post processing and they always need some sharpening. I am getting OK images but nothing I'd wow about.

[geordie graham]

I also have this lens on my K10D and thought I was going to get pinsharp images all the time.I think my problem was that I thought 500mm meant that birds 100/200 yards away were going to be superb images and all I had to do was crop them.I totally agree what people say about Graham`s images but could you give us an idea Graham of how close you usually get to your subjects.I have Elements 5 and have seen pictures transformed using this.I have just bought a Manfrotto 055 tripod and the Manfrotto 393 head (50th birthday pressie) and have found this to be a very sturdy yet smooth mounting.To get better pics I think I will have to invest in a 500 f4.5 prime but that will be way into the future (wife/money permitting)

Graham

[eeyore]

Originally Posted by glsammy

I also do a lot of post processing, if your not doing this, this could well be the reason your seeing such a difference.
.

thats particularly true if you are using RAW - canon raw is always soft out of camera as there is no sharpening applied in camera (unlike with jpeg) - this is a good thing once you get used to it as it allows you to be more discrminating on how and where it is applied during your light room sessions.

[glsammy]

Just to give you an idea of what I do, here's a shot I took today, without any editing, straight from the camera.
I don't shoot RAW at the moment, but I switch off all camera adjustments, so the image is very much the same as if it were RAW.



Here's the finished image:



This one is almost full frame, cropped to 1600X1100 pixels. I was only about 20ft away from the Heron, which was very obliging staying with me for almost an hour.
The shot was at 363mm.

Here's a couple of other shots taken today:





Again I was quite close to the bird. These were again taken at less than 500mm. I was too close for 500mm. They were both full frame shots.

Here's an example taken at 500mm.

First the image straight out of the camera:



Now after my editing:



I hope they offer you some help.If you think it may well be the editing that's letting you down, drop me a PM and I'll send you the details of what I do. I use Photoshop CS2, but what I do I'm sure is possible with almost any software.

[JonSadler]

Graham,

You are PP wizard! Mind, you need a decent photograph to start with. I think this is where I am slipping up.

As normal very nice shots.

Jon

[Chris Hammond]

Thanks everybody, there's a fair amount of food for thought there.

To answer a few points:

I shoot a combination of Raw and Fine Jpeg. I often only use the jpeg as they seem decent enough for net use.

I have been shooting virtually everything at f6.3, but having read Graham's comments re the Sigma's sharpness when wide open on another thread I have been trying to keep the aperture as narrow as at least f8. To be fair I've taken very few shots since making this change, but will post any future results for comparison.

As for my editing process, well to be honest I sometimes tweak the slider controls in Photoshop a little, but that's about it.

BTW I'm using Adobe Elements Five.

The distance from subject may be key. I usually have to crop my images to make the subject big enough in the frame. Even at full frame though my pictures have seemed a little soft.

I will try and get a few more pictures taken at f8 and see if this improves things before looking for other possible gliches.

Graham, I will pm you as advised, thanks very much for the offer of help.

[ChasCreek]

Originally Posted by glsammy

Just to give you an idea of what I do, here's a shot I took today, without any editing, straight from the camera.
I don't shoot RAW at the moment, but I switch off all camera adjustments, so the image is very much the same as if it were RAW.


I hope they offer you some help.If you think it may well be the editing that's letting you down, drop me a PM and I'll send you the details of what I do. I use Photoshop CS2, but what I do I'm sure is possible with almost any software.

Interesting to see that your 'originals' are comming out as many of mine do, I though I it was just me! (I shoot raw), probably 80% of my images are like this others are somewhat sharper in the original but that is using the Sigma at shorter focal lengths and closer to the subject in good light.

My post Photoshop editing certainly doesn't improve my pics as much as you are achieving - I would also be interested in what you are doing in Photoshop

[eeyore]

Originally Posted by ChasCreek

Interesting to see that your 'originals' are comming out as many of mine do, I though I it was just me! (I shoot raw), probably 80% of my images are like this others are somewhat sharper in the original but that is using the Sigma at shorter focal lengths and closer to the subject in good light.

My post Photoshop editing certainly doesn't improve my pics as much as you are achieving - I would also be interested in what you are doing in Photoshop

chas - what are you using as your raw converter ? - a lot of the sharpening and general adjustments should be done at this stage of the workflow rather than in photoshop (unless of course you are using the adobe camera raw plugin in photoshop as your converter)

[ChasCreek]

Hi eeyore,

I am opening straight with Photoshop CS3 although the CS3 launch initially opens the NEF file in a seperate RAW 4 window for adjustments before selecting it to open in CS3.

I prseume this is a CS3 plugin as part of the standard set of plugins to handle raw images such as the NEF file (It isn't a plug in that I have added).

I do my manipulation (colour temp, sharpening, blacks, contrast, exposure etc in the RAW 4 window within CS3 and when it finally opens in CS3 proper I only use that to save out.

[BruceP]

Originally Posted by eeyore

chas - what are you using as your raw converter ? - a lot of the sharpening and general adjustments should be done at this stage of the workflow rather than in photoshop (unless of course you are using the adobe camera raw plugin in photoshop as your converter)

Sharpening should be performed as the last step, or at least sharpening for output should be. Therefore, if you are taking the image into photoshop or some other editor after the RAW conversion software, you should not do any sharpening at the conversion stage.

[DavyG]

Thanks to Graham for giving me an insight into his pp workflow, he certainly produces excellent images using it.

I've often felt that pp is almost a dark art and it's mysteries are generally kept quiet.

I've been studying a course available from a well known online training establishment, the course is called:

Photoshop CS3 Sharpening Images

It's hard going at times but it is worth a look, I learn a bit more each time I sit down and watch another lesson.

Dave

[glsammy]

Originally Posted by BruceP

Sharpening should be performed as the last step, or at least sharpening for output should be. Therefore, if you are taking the image into photoshop or some other editor after the RAW conversion software, you should not do any sharpening at the conversion stage.

Yes, sharpening is the last thing I do in Photoshop, after cropping or re-sizing and all the other adjustments. I finally run neat image over selected background parts if necessary.

[geordie graham]

What I do first in Elements is adjust the levels then alter the Contrast/Brightness
Then I use Unsharp Mask and then I crop.Could anybody tell me if this is right?.It is a bit of a minefield to start with but still fun.

Graham

[glsammy]

Originally Posted by geordie graham

What I do first in Elements is adjust the levels then alter the Contrast/Brightness
Then I use Unsharp Mask and then I crop.Could anybody tell me if this is right?.It is a bit of a minefield to start with but still fun.

Graham

Crop first! Do the sharpening on the finished image, after all the other adjustments. The amount of sharpening you do is directly related to the final image size, so to sharpen first, then crop will not give you the best looking image.

[geordie graham]

Originally Posted by glsammy

Crop first! Do the sharpening on the finished image, after all the other adjustments. The amount of sharpening you do is directly related to the final image size, so to sharpen first, then crop will not give you the best looking image.

Thanks Graham will do that from now on.I will try it on some my originals from previous photo`s.

Graham

[eeyore]

Originally Posted by BruceP

Sharpening should be performed as the last step, or at least sharpening for output should be. Therefore, if you are taking the image into photoshop or some other editor after the RAW conversion software, you should not do any sharpening at the conversion stage.

I quite agree bruce - i didnt make my self clear. What i meant to say is that a lot of images need never see photoshop - if they were properly composed etc in camera you can do everything that is needed (wB adjustment, exposure correction and finally sharpening) in your raw converter. ( though admittedly if you have cS3 you may well wish to just use this as your converter also)

[Chris Hammond]

Finally managed to find the time and a willing subject to photograph following the advice given on this thread. It isn't anything too exciting, but I'm pretty satisfied with the sharpness. It's a result of 'backing off' the full zoom a little and shooting at f8. Thanks for the help everyone, I'm sure my pictures are going to improve quite noticeably in future.



Regards Chris

[Rob Jones]

Originally Posted by Chris Hammond

Finally managed to find the time and a willing subject to photograph following the advice given on this thread. It isn't anything too exciting, but I'm pretty satisfied with the sharpness. It's a result of 'backing off' the full zoom a little and shooting at f8. Thanks for the help everyone, I'm sure my pictures are going to improve quite noticeably in future.



Regards Chris

Now that is nice and sharp Chris!

[DuncanE]

At the risk of sounding stupid. Should you use the RAW converter sharpening tool at all? or should it all be done once finshed. I hear too many things about sharpening and not sure on the correct action.

I normally sharpen a little on the RAW covertion then additional sharpen at the end of editing - it does give me similar results to just sharpening at the end.