Panasonic Lumix FZ38

[NickB]

http://www.aakatz.com/whitepaper/whitepaper/part13.htm

This gives an analysis of telephoto, macro and close-up lenses with example pictures....
N

[NickB]

...and this is about close-up lenses..
http://www.naturemagnified.com/2009/11/ ... enses.html
N

[Jack Harrison]

Useful links those.

+2 dioptre is the same thing as a 500D a measure of focal length = 500 mms (50 cms) so maximum possible distance to subject is 50 cms

+4 is the same thing as a 250D focal length = 250 mms (25 cms) so maximum possible distance to subject is 25 cms

A +4 / 250 will of course give a bigger image than a +2 / 500 but operates at a much closer distance - not always an advantage.

The benefits of achromatic (doublet, two-element) lens are mentioned in those links. The dedicated Panasonic lens which started the current discussion is an achromat so is good. I just went down a slightly different route using an achromatic lens that happened to be cheaper but more hassle.

I would suggest to anyone interested in getting an achromatic +2, do a web search and if/when you find one, get it. Don't worry if the diameter is wrong - adaptors can deal with that. I in fact have two +2 achromatic close-up lenses, one for each camera, but they weren't easy to find. But if you are in luck, they are not expensive, certainly much cheaper than a so-called dedicated lens which is little more than a crafty way of making you spend money for a virtually identical product.

Jack

[Jack Harrison]

I’ll try another way to explain how close-up lenses work. A simple screw-in close-up lens is discussed here NOT special macro lenses as favoured by DSLR users.

Use a magnifying glass. Hold magnifying glass to your eye.
You will find that you can focus on objects much closer than without the magnifying glass. But you cannot focus on distant objects.
This is exactly how a close-up lens works on a camera. Your eye does not need to employ special tricks to use a magnifying glass; nor does your camera.

Close-up lenses are occasionally called filters. This is incorrect use of the word filter, but it doesn’t matter all that much. I presume the word filter is convenient for any device that screws into the camera’s own lens.

Jack

[EricY]

NickB, many thanks for posting those links. I know Alan Katz's white paper from Sony DPreview forum, as i have some sections of it bookmarked but not that one. I have tried to get the sony M3358 but no one seems to have it in stock now. Alan got good results stacking it with the 1758tc that I already have. Will have to try that with the Hoya when I get it. I can see I must do a lot of practise before the BF season to try & match the photos i see here. Eric

[Paul Wetton]

Question for all you FZ38 experts (Jack).

My mother has this camera which pertains to have a zoom of if I remember correctly 18 x optical.

She's taken plenty of photos on the best quality setting as far as I am aware but when the photos are zoomed in on the PC or especially on the TV anything past 2 x or 4 x zooming i.e. cropping gives very grainy and what looks like to me pixelated pictures.

The CCD is around 12 MP so in theory should allow a crop factor much bigger than this. Are we doing something wrong with the camera or do other people get this same effect.

Please let me know.

[NickB]

Are we doing something wrong with the camera or do other people get this same effect.
Please let me know.

I used to own an FZ50 - a pre-cursor to the FZ38 - and that had 12x optical zoom. I think the results you get are likely to be the best you can get, unfortunately, since the lens system on these cameras is covering an awful lot of focal lengths and something has to give....and that seems to be IQ at extreme zooms. Certainly that was my experience with the 10mp FZ50, especially if the image was enlarged. I remember Jack earlier mentioning the 18x zoom was better for marketing purposes than actual use!
I think the reason people here have embraced the FZ38 is its (obvious) quality in taking macros.
An owner, like Jack, may have some more wisdom to impart....
N

[Jack Harrison]

18x zoom means 18 times the widest setting. So if the maximum wide angle is very wide then the most extreme zoom is less impressive than it might seem.

The FZ 38 goes from 27 mms to 586 mm. My Canon A650 has a nominally smaller zoom range of only 6x but because it starts from 35 mm at widest, the telephoto end is 210mms.

Thus “so-many-times zoom” is only part of the story.

I cannot see why Paul’s mother gets a pixelated result at higher zoom setting UNLESS she is using digital zoom. Check that out Paul.
Digital zoom is frankly pointless (subsequent cropping achieves the same result) EXCEPT that it might appeal to those who don’t post-process. In effect the camera is doing the cropping in situ.

So digital zoom and massive optical zoom ranges could be of value to some customers but the real winners are the salesmen. They are gimmicks that sell.

You did imply Paul that your mother uses low ISO settings. If the FZ38 is used in totally automatic mode, it is possible that the ISO is set by the “intelligent” camera – it knows best. Frankly like all cameras with smaller sensors, high ISOs give very unsatisfactory results. On the FZ38, 200 ISO is just about OK but 400 and above are useless.

Jack

[Paul Wetton]

You've probably hit 2 nails on the head there Jack.

I agree that more zoom equals poorer quality but always for some reason thought that if you keep within the optical zoom range then it should allow crop factors of 10 fairly easily. Maybe not so with a smallish CCD.

My Mum will definitely be using the (un) intelligent auto setting which is likely giving high ISO ratings especially as she's been using it in rain forest which is pretty dark.

It's most likely a combination of high ISO 400+ and using the top end of the zoom setting at 18x.

Thanks for the comments.

[celery]

Thanks very much for all the replies to my query about close-up lenses.

After reading the information provided by Jack Harrison and that in the links suggested by NickB I believe the penny has finally dropped!

Thanks also for the extremely generous offer of one-to-one tutoring from Sussex Kipper. No doubt you'll be pleased to hear that I reckon I've cracked it without the need for you to talk me through it.

Incidentally Jack, despite the fact you were happy to dismiss it as a 'gimmick' I've found that if you don't 'tell' the camera it has the conversion lens attached the image you get on the viewfinder is one of darkness accompanied by a circle of light in the middle. Rather like the what you see emerging from a long, dark tunnel or that which appears in the title sequence of the James Bond films.... POW!

Now, I believe I've seen a glimpse of sun through a crack in the clouds... I'm off into the garden to try out my new techniques. Perhaps I'll find the last berry to remain unmolested by the blackbirds or maybe an interesting leaf...

[Neil Hulme]

Hi celery,
Glad to hear you've cracked it! With 'conversion on' set via the menu, while in P lens mode (via dial), and adaptor and close-up lens attached, you will probably have already sussed that your working distance (irrespective of how much zoom you are using) is restricted to about 35-50 cms, otherwise you won't be able to focus. You will soon get the hang of this distance from insect when practising in the field. And that's the most technical a photography post you'll ever see from me .
Good luck, Neil

[Jack Harrison]

celery took me to task (nicely)

Incidentally Jack, despite the fact you were happy to dismiss it as a 'gimmick' I've found that if you don't 'tell' the camera it has the conversion lens attached the image you get on the viewfinder is one of darkness accompanied by a circle of light in the middle. Rather like the what you see emerging from a long, dark tunnel or that which appears in the title sequence of the James Bond films.... POW!

I have never used the "telling the camera" because my method is slightly different in that I use my own lens rather that the Pansonic system which I believe uses a special adaptor. What you describe is "vignetting" and most probably caused by the adaptor sticking out the front of the main lens (or something along those lines).

Vignetting: http://en.wikipedia.org/wiki/Vignetting

I have precisely the same problem with a graduated neutral-density filter that I use to darken skies in landscape shots. Yes I know that post processing helps but that can only do so much. Strong advice about graduated ND came from the landscape Photographer of the Year, Antony Spencer. If I try to use my Canon camera at maximum wide angle I get that vignetting. What that means in practice is when I use that I cannot use the very widest of angles if I have the graduated filter attached.

I'll play with that "telling the camera" mode on my FZ38. I cannot be sure, but it won't surprise me if what it in effect does is to ensure that maximum wide angle settings are inhibited.

Play time.

Jack

[Jack Harrison]

Yes, "conversion" set-up did what I expected. It inhibits the the widest end of the zoom range to avoid vignetting. It's clever but I am far happier with the understanding of the principles of optics than I am with computer technology. So in effect, I had been working from first principles and had come up with exactly the same answer as those clever computer programmers at Panasonic.

I digress a little. Yesterday I had the biometry on my left eye to prior to a lens implant operation next Thursday to deal with a cataract.. Of course, as you might imagine, I was fascinated by the optical tests to determine precisely what implant lens I need. Needless to say, I bandied about technical terms like diopters, focal lengths, etc. I don't know whether I impressed the technicians with my understanding. More likely they thought: "here's another know-all". (I am not inviting your comments thank you).

Anyway, I had realised that after the implant, my left eye will be more or less (with luck) right for distance vision. Of course, my existing spectacle prescription will then be useless for the left eye and it will take a few weeks before things settle down and can get a new prescription and glasses. In the meantime, I could wear a monocle for my right (serviceable) eye. I suspect that would be extremely difficult . (Neil. You once met Patrick Moore. Could you ask him how he keeps his monocle in?) My solution - and apparently I had re-invented the wheel so to speak- is to remove the glass from the left eye of my existing specs. So I anticipate looking rather eccentric over the coming weeks wearing spectacles with on one piece of glass.

Jack

[NickB]

As Neil says, the "conversion on" for Panasonic's close-up lens integrates that lens into the Leica lens system to create a short macro lens. Adding a magnifying diopter to the front is not the same thing, since all it does is magnify the normal image produced. Hence, with the "conversion on" + lens, there is more blurring of the background (narrower depth-of-field) than if you use the telephoto and add a diopter....
N

[Jack Harrison]

Nick:

As Neil says, the "conversion on" for Panasonic's close-up lens integrates that lens into the Leica lens system to create a short macro lens. Adding a magnifying diopter to the front is not the same thing, since all it does is magnify the normal image produced. Hence, with the "conversion on" + lens, there is more blurring of the background (narrower depth-of-field) than if you use the telephoto and add a diopter....

That flies in the face of basic optics. The "dedicated" Panasonic lens is no more, no less than a +2 dioptre achromatic supplementary which does more-or-less the same thing as a true macro - but less well of course. But it is Panasonic's interests to suggest that they are offering something special I will do a side-by-side test against using conversion/no conversion with all other settings the same and I do not expect to see any differences.

And Nick . (MS Word says "Fragment - consider revising") You know that I am a pedant (where is that recommendation for "pedant of the year"?) I will concede that spelling of dioptre is ambiguous - some (American?) spell it diopter. So with pendant mode now engaged. Dioptre (diopter) is not a noun. You can add a +2 or + 4 diopter lens (ie, used as an adjective). But you cannot add a "diopter" any more than you can use Photoshop to add a "blue". You might however use Photoshop to add a blue sky.

Jack

[Padfield]

When it comes to pedantry, Jack, I am an acknowledged master!! 'Dioptre' is a noun - the related adjective is 'dioptric'. But you are right about the usage, since it is (most commonly used as) a unit of measurement and makes no sense without an attached numerical multiplier.

Guy

[NickB]

..and now there are two Nominations for "Pedant of the Year"......
..any more nominations?
(Though I bow to Jack's superior wisdom and make an acknowledgement of my sloppy use of English, Guy...)

[Jack Harrison]

Guy pedanticised***:

'Dioptre' is a noun

So presumably "pedantic dioptre" would be correct English as would "dioptric pedant".
However "pedantic dioptric" or "dioptre pedant" would be incorrect.

Glad we cleared up that one.

Nick has pointed out privately not wishing to shame me too much in public, that the conversion mode on the FZ38 might do more than just restrict zoom range to avoid vignetting. It could, he suggests, actually alter the internal geometry of the basic lens. Good point that I hadn't thought of. But there is no noise when conversion is selected - as there is when zoom is changed - so despite Nick's imaginative reasoning, I suspect that he is not correct.

You might note the time of this post, 0203 hours. I had got out of phase with my sleep pattern through watching the cricket in Australia.

***I read the other day that the English language has 1,000,022 words. Make that 1.000,023 now.

Jack

[Vince Massimo]

Jack,

GO TO BED.

[Jack Harrison]

Playtime over.

With the achromatic close-up lens attached, I can detect no optical differences between my method using “normal mode” and the dedicated “conversion” mode. In neither case is maximum wide angle available as explained before.

However with the conversion activated, flash seems to be inhibited even if “forced on” regardless of the mode selected on the dial. I might have missed a trick here so I could be wrong. Now the use of flash is often a bad technique as it can produce a decidedly unnatural look. But there are occasions, eg wind shaking foliage, when the use of flash can be useful to freeze that movement.

I will be remaining unconverted (and not even tempted by Paganism, despite my celebration of the winter solstice!)

Jack