I'm a bit surprised there isn't more of a difference to be honest. I have a Samsung and I bought it expecting it not to hold it's value anywhere near as well as an equivalent Pentax. I also bought mine as a bit of a steal (last one in the shop) so I am doubley happy!

Thanks for the info K10d. Reassuring to know someone else uses Marumis with good results.

Stefan, I have to admit I don't really understand the explanation in the link. However, my understanding of polarisers is very basic. I would have thought a circular polariser attached backwards would act as a linear polariser. Would the light not pass through the quarter wave plate first and then be polarised by the front plate? Anyway, I hadn't thought about the fact you would get a polarised effect. Having a think about it, I don't think that is too much of a problem for me.

I'm tempted to give it a go and see how I get on.

Cheers

wg

'lo All

Just wondering if anyone has a Marumi DHG circular polariser. I understand these represent pretty good value for money:

http://lenstip.com/115.4-article-Polarizing_filters_test_Results_and_summary.htm...

Currently I have a linear polariser which works reasonably well. Now, I don't want to re-open a conversation about whether linear polarisers work with Pentax DLSRs or not. I don't seem to get lots of problems with the metering but I haven't tested it extensively so it could be my inexperience or that the difference is too small for me to notice.

The main reason I am considering getting a circular polariser is to use it alongside the linear polariser as a variable ND. I've not tried it out but apparently if you mount a linear polariser on top of a circular polariser you can vary the amount of light you let through. The Marumi is relatively thin and my linear polariser is really thin so vignetting would hopefully be minimal.

Since the Marumi is good value I figure I can't really lose (well, not more than £30 and even then I get a circular polariser to replace the linear one and therefore if there are some metering issues I'm not noticing then it will eliminate them).

However, I was wondering if the Marumi has a filter mounting thread on it. I believe some polarisers don't and therefore that would prevent me using it this way.

So, in a roundabout way my question is "does the Marumi have a thread to mount a second filter on it?". Anyone know?

Cheers,

WG

I believe you're right Stefan - it does have a slightly wider max aperture.

I would say the pros are:
- Silent focussing
- Slightly wider aperture at the long end
- In-lens stabilisation (? - unproven if this is better than in-body but the option to use either can't hurt)

Cons:
- Additional weight

...and the unknown is the picture quality. I would guess the lens formula is slightly different as the max aperture has changed and there is likely a floating element inside for the stabilisation (that's my understanding of how it works but I could be wrong:blush. Given that the pros and cons are relatively minor I would be nervous switching from a lens I know is great to one that may have a slightly different performance. There must be some direct comparisons out there from people who have used both.

I am a naturally suspicious person so I would be slightly aprehensive of the request. Are we talking about a not-for-profit organisation creating textbooks or one that is planning to publish and make profits from the book?

Having said that, I can see the argument that the Danish textbooks market may be very limited and therefore I imagine they would try and reduce the number of contributors they compensate.

I think Gwyn's suggestion is a good one - i.e. to confirm that this would only be for the Danish language version.

But all that aside, congratulations! Someone has seen your work and would like to publish it.

Hi Chris

How well does it function with the Sigma 100-300? I know the compatability chart says it doesn't but I am sure other have said that autofocus still works in bright conditions. If you have tried it, is the image quality drop off significant?

Cheers

WG

If you have just the one lens then I would consider getting something in a different range. As peple have already pointed out, the kit lens is actually quite good and you will probably benefit from a more varied lens arsenal. Manual primes are a cheap way to do so but they don't suit everyone. They require more patience and skill and some people don't like their restrictions.

If it is a replacement you're after then there are lots to choose from. Have a think about what would suit your needs. Don't get a lens and try and work around it. If you like landscapes I would have thought that a lens with a 16-18 wide end would be useful (like the kit lens). If you get one that starts around the 20s you might be dissapointed. Then consider if you would like more range. If you want it to go out to the 70mm range then you have narrowed down your options. If you're not bothered then again you have narrowed things down.

Personally I can only speak for the Sigma 17-70. It suited my needs (wider range and pseudo macro capabilities) and image quality wise it is a significant improvement on the kit lens. But there are people here with more experience of standard zooms who will be able to advise you on all the options.

A K20d (or at least a GX20) isn't much good with an R72 filter. The IR pass filter is much stronger so longer shutter speeds are needed and the results are blurry and poor unless the subject is completely still (and even then the shots are noisy).

Much easier to convert an old camera! Point and shoot anyway. Tested the theory with a really old digicam and then modified my old Kodak superzoom. It now takes IR heavy pics as standard and if you put the R72 filter in front of it the shots are brilliant. Obviously not SLR quality but better than my GX20 with filter attached. The only issue at present is that it sometimes struggles to focus. Scouring the interweb tells me that putting a clear glass filter of similar thickness in place of the IR pass filter should correct that. Wondering if I can get some microscope slides and clip one down... After that I'll be looking to permanently attach an R72 filter to the front of the lens.

I'd love to have the cash to spare to convert an old Pentax DSLR. I'd be fairly confident but I just can't justify the expense.

Sounds like sticking to the circular filters is the plan for most applications and then a square set for some graduated NDs.

Can probably get away with:

Walkabout lens:
- polariser
- an ND or two

Landscape lens:
- polariser

Tele and macro:
- nothing

Cokin/square filters:
- ND grads to fit the walkabout and landscape lenses

I probably wouldn't know what to do with any other filters anyway. I've already found out that an infrared filter is useless with the GX20. I get better pics from the old Kodak superzoom I took apart and removed the ir pass filter from.

Thanks for the advice and comments everyone. Always useful stuff to consider when I ask questions on here.

Cheers

Aha! But doesn't that give the same problems? You still can't use your lens hood that way. Are the Cokin filters not particularly good quality then?

Maybe it would be false economy to buy into the system. Perhaps I should be saving for polarisers for my walkabout and landscape lens (once I get it...) and then some NDand ND grad filters for both.

Hmmm.