new lens not sharp

[wommby]

Hi All,

Here are a couple of images I took with the old lens I have 24-85mm taken at 24mm wide, on tripod, remote release. Taken at f22 so great depth of field.

These are taken with hyper focal focusing and the front fern leaves are about 18inches from camera.

This is what I am trying to achieve with my new lens but cannot get sharp shots.

Deb

[Colin Southern]

Hi Debbie,

I'm afraid that I'm getting to the "who knows" point

I had a read of all the reviews on the Fred Miranda site http://www.fredmiranda.com/reviews/s...&cat=28&page=1 - have a read for yourself - there are a mix of opinions. Some comment on the lens being less than perfect areound the periphery - others comment on performance wide open (which is a challenge for any lens) - and perhaps there are also sample to sample variations? I'd be inclined to just see how it performs in practice, paying particular attention to focusing and sharpening.

To comment on your comment about using AF for landscape ... yes, absolutely - BUT - you need to pick the point that it focuses on - don't just let the camera pick any old point.

In terms of the samples you've given, with the new lens, it's looking "OK" towards the centre (not great, but that could just be a bit of lens performance and a bit of the consequences of F11) - I've certainly seen better and worse, but the clarity of the detail around the outside does look a little worse (with perhaps a touch of CA as well). The 100% crops probably aren't a fair comparison with the "old lens" examples though, as in both cases you've shown a crop of a nearer element, and no-doubt, the element in the scene that you've focussed on?

The shot taken from further away is definitely sharper, but then again, I'd expect it to be anyway.

All I can suggest is to try some back-to-back testing - perhaps a series of shots to evaluate centre sharpness at all apertures - and the same for peripheral sharpness - and try to work out if it has a "sweet spot" (and repeat at several different focal lengths).

Keep in mind too that even it it's performance does drop off in some areas, it's probably something you'll only see when evaluating full resolution images at 100%, which is NOT how we see them either online or in printed form, so it may not be a big deal.

Sorry I can't be more help

[wommby]

Thanks Colin,

Will take a lot more photos yet before I decide. I bought it primarily for underwater so hopefully it will perform O.K in this area.

Thanks again for your help and I will post some images when I get what I think is acceptable
Deb

[Black Pearl]

The first is the sharpest as you've actually focused on the subject - your lens is not faulty and is working perfectly.

The second is very close so I'm guessing your manual focus point was very close to where the camera focused in the first shot.

The last shot has a greater DoF reach beyond the subject simply because the subject is further into the whole scene.

I know what you are getting at and I know what you are trying to achieve but it isn't possible to have everything from very close to infinity perfectly sharp in one shot. Whether you use AF, MF or pick a theoretical point to achieve maximum DoF field there is still going to be an area in front that is soft and possibly an area at or close to infinity that will be soft. If you really, really must have every bit of your picture sharp then take a series of files moving the focus point through the scene and stack them together with something like Helicon Focus.

[wommby]

The first is the sharpest as you've actually focused on the subject - your lens is not faulty and is working perfectly.

The second is very close so I'm guessing your manual focus point was very close to where the camera focused in the first shot.

The last shot has a greater DoF reach beyond the subject simply because the subject is further into the whole scene.

I know what you are getting at and I know what you are trying to achieve but it isn't possible to have everything from very close to infinity perfectly sharp in one shot. Whether you use AF, MF or pick a theoretical point to achieve maximum DoF field there is still going to be an area in front that is soft and possibly an area at or close to infinity that will be soft. If you really, really must have every bit of your picture sharp then take a series of files moving the focus point through the scene and stack them together with something like Helicon Focus.

Thanks Robin,

I think I am trying to be too fussy. If everyone else has to face the same senario and they can get good shots then I will just have to learn to capabilities of the lens and what it can do and not what I expect it should do. Hope this makes sense. I am happy with the lens. Here is a couple of shots I have taken with it at 17mm wide. One is in auto focus and one was taken with the hyper focal focus. And a third one for no real reason.
Deb

[Colin Southern]

Hi Debbie,

Are you applying output sharpening to these after you down-sample them?

[wommby]

Colin,

No, I did capture sharpening you suggested at the beginning of the topic. So, what do I do once I down size them? Do I need to do this every time I load something on the internet?

Deb

[Colin Southern]

Colin,

No, I did capture sharpening you suggested at the beginning of the topic. So, what do I do once I down size them? Do I need to do this every time I load something on the internet?

Deb

Hi Debbie,

You need to apply sharpening at least 3 times in your workflow ...

1. Capture sharpening (300% @ 0.3 pixel on the full resolution image)

2. Content / Creative sharpening (it varies, but often around 40% @ 4 pixels, again, on the full resolution image)

3. Output Sharpening. If you down-sample with Photoshop's bicubic (as opposed to bicubic-sharper) algorithm then a typical output sharpen is usually in the region of 50 to 125% @ 0.3 pixel (ie do this adter you've down-sampled).

Why not give it a try and see what you think? Just toggle the preview off and on a few times to see the difference it's making.

[wommby]

Colin,

1 quick question. In steps 1 & 3 you are using 0.3pixel and in step 2 is the to be 4.0pixel or 0.4???

Will try this as soon as I clarify the above.
Deb

[Colin Southern]

Colin,

1 quick question. In steps 1 & 3 you are using 0.3pixel and in step 2 is the to be 4.0pixel or 0.4???

Will try this as soon as I clarify the above.
Deb

Hi Debbie,

It's 4.0 in Step 2.

Basically ...

- Apply capture sharpening whilst looking at the image at 100% magnification, and you'll see it get "sharper" (at anything less than 100% magnification you probably won't be able to see the change)

- Apply content / creative sharpening whilst looking at the entire image at a reasonable size on your screen - again, you'll see a definate "clarity" to the image. Although I say 40% @ 4.0 pixel, these are just starting points - it's pretty typical for portraiture, but the bottom line is "use whatever makes the image look better" - always done at full resolution though (after cropping is also OK, so long as the image isn't severely cropped)

- Output sharpening (for display) is always done after down-sampling - one has to be careful not to over-sharpen at this stage, but if you look carefully (at 100% magnification) you should see an improvement in the image. If you start to get frosting though, you'll need to back it off a bit. Works best for omages in the region of 1000 px x 700 px.

[wommby]

Thank Colin, have been trying this out and WOW what a difference. I just never really knew much about sharpening but thank you for all of this. I have written it all down and will practice now and post some images on a new forum

Deb

[Colin Southern]

Hi Debbie,

You're welcome

And don't worry, you're not alone. It's something I see quite often -- many don't seem to realise that correct sharpening has a far bigger influence over the quality of an image than the inherant differences in sharpness between "lens A" and "lens B".

[wommby]

Hi Debbie,

You're welcome

And don't worry, you're not alone. It's something I see quite often -- many don't seem to realise that correct sharpening has a far bigger influence over the quality of an image than the inherant differences in sharpness between "lens A" and "lens B".

This forum is just wonderful and I have learnt so much in the past few weeks reading other posts etc. You really are a wealth of information and most of us enthusiasts wouldn't know what we know without people like yourself.
A really big THANK YOU

Deb

[Colin Southern]

This forum is just wonderful and I have learnt so much in the past few weeks reading other posts etc. You really are a wealth of information and most of us enthusiasts wouldn't know what we know without people like yourself.
A really big THANK YOU

Deb

Thanks Debbie

There will always be those who know more than us, and those who know less -- the trick is to learn from those who know more, and pass it on to those who know less (as payment!)