topic A33 Aperture control doesn't seem to do anything. in Alpha & NEX interchangeable lens cameras

A33 Aperture control doesn't seem to do anything.

pvg2001 — Tue, 01 Nov 2011 17:07:10 GMT

I have never been able to get any background blurring with my A33 as per the manual - lens Tamron 18-200.

Tech Support doesn't help either but sends me links related to "F" setting which I already know about.

I have attached 4 photos taken on Sunday;

1 - SCN setting for Macro

2 - SCN setting for Portrait

3 - Aperture to 3.5 - the shortest I can set

4 - Aperture to 22 - the deepest I can get.

I can't see any differences in these photos..... Can you?

Any feedback, advise, suggestions would be very much appreciated.

paul2011

A33 Aperture control doesn't seem to do anything.

Mick2011 — Wed, 02 Nov 2011 08:09:53 GMT

Hi Paul

I downloaded these and had a good look. I agree the difference is very subtle... although the most obvious (as you'd expect) is between the f3.5 and f22 versions.

According to your EXIF data, you have the 18-200 set to a wide 22mm for this test. There are a number of factors playing hardball against a blurred background here.

First is focal length. Wide-angle shots are unlikely to give you a blurred background unless you're focused really close, like in the region of half a metre. If you tried the lens set to 80mm, or better 200mm you'd see the difference straight away and it would work at reasonable subject distance. The closer the better, though, for maximum effect. It's a fairly complex explanation, best understood by trying it out!

Second is the size of the sub-APS format sensor, which by its nature gives you more depth of field than a full-frame chip. Third is the lens itself; the optics in a super-zoom like the 18-200 are very complex and geared towards combatting distortion, rather than engineered to give pleasing bokeh.

Hope that's of some use.

Cheers

Mick

A33 Aperture control doesn't seem to do anything.

pvg2001 — Fri, 04 Nov 2011 09:23:31 GMT

Hello Mick

I appreciate your reply, thanks. Do you work for Sony?

On all of the shots (and normally) , I use the 1-spot focussing and all my pictures are taken using the lowest F setting that I can. I use this because, as you have seen, there is virtualy no blurring which is what I want to get.

The manual says that I can get this and this is partly why I bought this particular camera and why I am very frustrated with it.

Looking at the photos that you have seen, why isn't there a difference between even the SCN photos?

Maybe my question to you should be - "If I took all of these photos again, how can I get background blurring using my existing lens? (I don't wany to carry any extra equipment.)

If you happen to work for Sony, then I will also say that:

1. the spot focussing has a problem deciding where I want it focus especially in low light and sometimes won't focus at all so I can't take the shot I want e.g. in a church where I can't use flash.

2. when videoing, the camera records all the noise when the autofocus is working. Spoils the videos.

3. Sony Support doesn't support my problems in video playback in PMB when after a reinstalltion of XP Home, so I can't play my videos any more. VERY unimpressed with that.

If you don't then thanks for "listening".

A reply to the first part would be great.

Thanks

Paul

A33 Aperture control doesn't seem to do anything.

Mick2011 — Sat, 05 Nov 2011 12:45:16 GMT

Hi Paul

I don't work on the technical support side as such, but Sony do pick up on comments made here, if that's what you mean. Always worth posting this kind of feedback on a separate post, ideally on one of the 'suggestions' threads, if you want to be sure of getting noticed

The issue you're struggling with isn't to do with focussing – you need to focus on the subject, regardless of the focussing method – nor are scene settings really relevant. Some scene settings will automatically select a larger aperture, which is the only thing they can do to affect the amount of blurring you get, but it seems you are happy to select that manually. So far so good.

Aside from keeping wide apertures (low f settings) you need to concentrate on two things:

First, don't use wide-angle (lens zoomed all the way out) as you will get too much depth of field, and even at f3.5 your backgrounds could stay quite well-defined... zoom in, the more the merrier, and as you do so your background will become progressively more blurred.

Second, get as close as you can to your subject, and choose a background as distant as possible beyond your subject. The closer you are, and the more distant the background, the greater the background blurring.

These two things are by far the biggest variables in achieveing a blurred background. After that, all you can change of any significance is the lens, and I'm afraid it can be quite a big change. Wide open and zoomed to 200mm your 18-200 is at f6.3, compared to more expensive zooms, the best of which are a constant f2.8. That's a big difference and it shows in the shots.

But do remember those two main tips: they should make a big difference on their own.

Cheers

Mick

A33 Aperture control doesn't seem to do anything.

pvg2001 — Mon, 14 Nov 2011 11:20:10 GMT

Hi Mike

Appreciate yourt reply and advise.

If you look at Test 3 and 4, these were both 2 metres from the centre of the fountain with a 1-spot focus setting.

I can't see any blurring at all, so where I am going wrong.

I feel like I am wasting my time with trying to get blurring as I usually now take everything on the smallest (3.4 or whatever the zoom gives) as in teh photos.

I would say that the closer I take phots to my subjest (e.g. portrait) then there is less background blur, whereas the further I am away and use the zoom, the more blur but then the photo is prone to camera shake because of the extended zoom.

I therefore have to disagree with your comment "first" - the higher the zoom (e.g. 200) the greater background blur. 3 shots attached. All from about 1m from the flower

These seem to be the opposite of your comments, so would be interested in anything further.

Bye

Paul

A33 Aperture control doesn't seem to do anything.

Mick2011 — Mon, 14 Nov 2011 21:56:50 GMT

Hello again Paul

Re: your original tests 3 and 4: even at 2m distance, with the lens zoomed out to 22mm you have very little background blur, because at such a wide angle setting, a lens will provide too much depth of field at that distance. I'd recommend reading up on this term, as it's fundamental to understanding why there is little or no background blur at this setting, and conversley why there is maximum background blur at 200mm.

This page explains everything you need to know (especially halfway down the page) with some good examples you might find instructive: http://www.mir.com.my/rb/photography/fototech/htmls/depth.html

Looking at your new examples, you demonstrate a similar result to previous ones with the flower (Zoom 18 at F4.JPG) although you are closer (1m) to the subject, so there is now a small but noticeable amount of background blur compared to your statue photos.

However the background blur is more noticeable as you zoom in to 35mm (Zoom 35 at F4.5.JPG) and very noticeable in the final frame at 100mm (Zoom 100 at at 5.6.JPG) which is as I would expect, and – I thought! – exactly how I described it in my last post. Sorry if that wasn't very well explained, but you have now demonstrated very well how this technique is supposed to work: if you had zoomed in to 200mm, you would have got a totally smooth, defocussed background at that subject distance.

You do have to take care with camera shake at 200mm, but in Aperture Priority (A) mode, with your lens wide open (f5.6) the camera will select a very fast shutter speed, especially if you have good light, so it shouldn't be a problem.

I can only refer you back to my two main points and assure you they are correct. The key with any photographic technique is to practice and experiment with it, but also to remember that no single technique is ideal for all photographs. Wide apertures are a great way to approach a lot of photography, but background blur is not always the result. It is the natural product of zoomed-in photos of very close subjects, and it gets harder to achieve the more you zoom out and the further away you place your subject.

Let me know how you get on. I'll be happy to explain further if you like

Cheers

Mick

A33 Aperture control doesn't seem to do anything.

pvg2001 — Tue, 15 Nov 2011 12:14:36 GMT

Hello Mike

Appreciate your time.

This is a last attempt. I understand the usage of the F or A settings to get background blur. Sony Support told me the same thing.

2 new phots attached. I see very little difference the depth of field between the shots.

Both pictures taken from 2 metres of the bottle.

1st picture - zoom 35 and F4.5

2nd picture - zoom 35 and F25.

What I expect is that the background from Pic 1 is much more blurred than pic 2. Is this right?

Maybe I am just expecting too much from the camera.

Pre-digital, when I used 3.5 for a portrait then all the background was blurred. Now it doesn't seem to make a lot of difference. F22 gave me everything in clear focus.

Unless you have somethog to add to this, then I will live with what I have, thank you for your help and probably go back to Nikon the the future.

Paul

A33 Aperture control doesn't seem to do anything.

Mick2011 — Tue, 15 Nov 2011 23:27:03 GMT

Hi Paul

There's a big difference there, if you look at the rooftops in the background. At f4.5 they're nicely defocussed; at f25 they're almost as sharp as the bottle. Also look at the foliage to the left and right of the frame in each example. The difference you see between those two frames is a perfect demonstration of shallow and deep depth of field, respectively.

With the first shot, the overall blurring effect is exactly what I'd expect with an f4.5 consumer zoom lens at 35mm on any APS-chipped camera body... I'll come back to that point later.

Let me just reiterate: you won't see a fully defocussed background with the lens set at 35mm unless the subject is much closer than 2m; it needs to be something like a metre or less. Or you use a longer zoom, say 70mm or more. To prove it, set it up again and try these two things:

Longer zoom = more defocussed background: set the bottle up at 2m distant again, but this time zoom in until the bottle fills the frame. Now zoom in to just the label on the bottle. Look at the background in each case; it will become more blurred as you zoom in.

Closer subject = more defocussed background: set it up again, but this time keep the lens at 35mm and instead move the camera closer to the bottle, around a metre away, so that the bottle fills the frame. Then move the camera closer still, so you see only the label, and refocus.

You'll get a subtly different blur to the first exercise, but the point to note is that the closer you focus the subject, the more blurred the background gets... crucially, the less you are zoomed in to your subject, the closer you have to be to it, in order to blur the background.

The only other point I would make is to make sure your background is sufficiently distant. You can see that in your first shot, where the distant rooftops are much more blurred than the foliage in your garden. Where there is detail right through the whole shot, from foreground to background (as there is with your example) the blur will become more pronounced with distance. Here's another example, from the link I posted last time, showing the same thing: http://www.mir.com.my/rb/photography/hardwares/classics/nikonfmseries/fm2/morris.htm

So I'd say you've done extremely well in demonstrating exactly what I was hoping to prove!

I did say I'd come back to your camera and lens. Lens first: an 18-200 zoom is not the best tool for this technique. You'll get much cleaner, more controllable and softer-looking background blur with a quality telephoto prime lens, like an f2.8 200mm, because that's what they were designed to do. You may well have used one on an old SLR and be struggling to reproduce that finesse with your more general-purpose zoom, and this might explain your frustration..?

And yes, the camera is a factor too. Like the vast majority of 'prosumer' DSLRs, the big full frame of the film-based SLR has been replaced with a much smaller, DX or APS-sized sensor chip. This has a direct impact on depth of field, working against the sort of effect you're looking for. The only way to combat this on most DSLRs is to engineer special lenses that counteract the 'small chip' problem. They're very expensive - I have a Nikon one that works very well indeed, but it cost £1500...

And I suppose this is where I'm bound to mention that it's not your A33 that's at fault, nor will a Nikon be any improvement... Nikon have used nothing but the exact same Sony sensor chips in their DSLRs for years however, with a bit of knowledge and practice, you can still 'do' the blurred background very convicingly on your DSLR.

Here endeth another long lecture hope it was of some help!

Mick

A33 Aperture control doesn't seem to do anything.

pvg2001 — Thu, 17 Nov 2011 10:08:33 GMT

Hi Mick

Thanks again for the "tome".

Close to the end.....

Looking at the original photos of the fountain and Test 3 and 4. (First posting)

They both look the same and so as a last question, "How can I get the background to blur with my existing lens?" as these 2 shots with 3,5 doesn't show any noticible blurring?

I have read all your comments and looked at the "Moments which is what I want from my lens/camera.

Is this possible, and if so what do I have to do to get this? A different lens?

Or, is this possible with my existing set-up?

The photo doesn't look the photographer was using a 18-200 Tamron!

Bye for now

Paul

A33 Aperture control doesn't seem to do anything.

Mick2011 — Thu, 17 Nov 2011 10:35:46 GMT

There's no mystery there: with your fountain shot you were too far from your subject, using too wide a zoom, to get any background blur. With those two things 'wrong', it barely matters if your lens is at f3.5 or f22, as you discovered.

Do you mean the photo that I linked to in my last post? That was a 300mm lens on a Nikon FM2 film camera, so no, it wasn't your 18-200mm zoom but yes, you should be able to get a similar result with your existing kit. You simply need to practice, persevere with it and you'll get there.

Ok, a better lens would certainly help – one that will let you get f2.8 (or even f3.5) at 200mm, instead of the maximum f6.3 that the Tamron has – but you really must be nearer the 200mm end of the zoom and you have to get the subject distance right.

Apart from that, all you really need is a pretty girl, a nice evening and an overgrown field in the country

Have fun!

Mick

A33 Aperture control doesn't seem to do anything.

pvg2001 — Sat, 26 Nov 2011 09:27:29 GMT

Hi Mick

Just in case you happen to have a look:

I still can't get my head around the fact that A22 and A3.5 make so little difference to the background blur.

So, let me ask a question using the fountain shots as example.

To me, basically no difference between the shots - same as teh bottle shots.

So, what lens would I need to be able to get background blur when I take a shot 2 metres from the fountain?

Bye for now

Paul

A33 Aperture control doesn't seem to do anything.

Mick2011 — Sat, 26 Nov 2011 12:15:46 GMT

Hi Paul

I can appreciate why you'd expect f3.5 to give much more background blur than f22. With a 'standard' or 'telephoto' lens it really does make a big difference. However, with a wide-angle lens it can be very hard to perceive any difference at all.

Let's get one thing straight: regardless of the type of lens, depth of field (DoF) always increases with aperture values. f22 gives more DoF than f3.5: a scientific fact based on the physical properties of all optics.

Look at the flower photos in this link: http://en.wikipedia.org/wiki/Optics#Photography - the f5 photo has way more background blur than the f32 photo, because you get way more DoF at f32. As I say, this happens with all lenses, without exception.

What happens to background blur when you try this experiment at different zoom values is not dependant on optics or science at all. It depends entirely on perception.

Look at the photos halfway-down this page: http://www.luminous-landscape.com/tutorials/dof2.shtml - the smallest zoom value (ie the most wide-angle photo, at 17mm) seems to have huge DoF; it seems as if everything is in focus, and there is little perceptible background blur: in fact the smallest zoom value appears to give no background blur at all. Notice those examples were all shot at the same aperture value (f5.6)

Now have a read of the article. Frankly, I personally think there is a qualitative difference with a very high zoom value lens (like the 400mm in this example) but you see the point: there seems to be no background blur at 17mm, even though there is. This is because there is so much more detail visible in the wide-angle view that the eye accepts the background as 'not blurred', even though it is.

So if you shoot the fountain at 22mm (as you did) it will appear to give you no background blur, whether at f3.5 or f22. This illusion will be even more complete when you're 2m from the fountain than 1m from the fountain. It would, however, have looked very different had you used a higher zoom value (~200mm) and/or got closer to the fountain (~1m): you'd have seen a lot more background blur in your photos.

You will undoubtedly see a more pleasing 'blur' effect with a 200mm prime lens than you will with your 18-200mm zoom, as I've noted in earlier posts, but this is really a matter of taste, not perception. I'd suggest persevering with your current lens until you see the sort of results I've linked to here, before you move on to pastures new.

That's about all I can tell you about it, hope you find it informative!

Cheers

Mick