55mm filter, 60mm lens

Pug · 14 Apr 2010 at 12:35

I know i can get a step-down converter, but i suspect i will see the "rim" of the filter in my wide shots?

On an 18-250mm lens, what focal length do people think this rim will dissappear?

TIA

Stupot_ · 14 Apr 2010 at 12:43

60 is a bit of a strange size. Do you have any other lenses, or plan to get any in the future? I'd be tempted to grab a 77mm step up + filter if you plan on upgrading to some nice glass

. I take it this is a CPL filter and not some UV junk.

Failing that... I can't answer your question

Johnny|lucidcomposure · 14 Apr 2010 at 13:46

hmm 5mm.
You might just get away with it and not clip the rim.

Remember on a 1.6x dslr you aren't using the entire of the lens so you can creep in on the lens radius a little.

Vertigo · 14 Apr 2010 at 13:59

Fstop11 said:
Remember on a 1.6x dslr you aren't using the entire of the lens so you can creep in on the lens radius a little.

True for EF lenses and third-party equivalents but not for EF-S or other equivalents which are only designed to cover the area of an APS-C sensor. I believe both the Sigma and Tamron 18-250mm lenses (of which the OP's lens is presumably one) are designed for crop sensors and thus will use the total "coverage" of the front element.

Pug · 14 Apr 2010 at 14:00

thanks!

Yeah its a £75 CP filter, so would like to re-use. Lens in question is a 18-250 Sony lens, which is a rebadged Tamron apparently.

Tomsk · 14 Apr 2010 at 14:16

Only way to find out is to try it.
However there are a couple of things in your favour, assuming you have a Sony DSLR.
Sony DSLRs are 1.5x crop whereas the Tamron lens will be designed to accomodate 1.6x crop DSLRs as well. Also Sony DSLRs have a 16:9 picture ratio which would conveniently crop out the corners of a normal 3:2 picture where you would most likely see the effects of your filter.

D.P. · 14 Apr 2010 at 14:50

Tomsk said:
Only way to find out is to try it.
However there are a couple of things in your favour, assuming you have a Sony DSLR.
Sony DSLRs are 1.5x crop whereas the Tamron lens will be designed to accomodate 1.6x crop DSLRs as well. Also Sony DSLRs have a 16:9 picture ratio which would conveniently crop out the corners of a normal 3:2 picture where you would most likely see the effects of your filter.

ERRRM, you got it the wrong way round with the sensor coverage. Sicne the crop factor is 1.5X the sensor is larger than Canon sensors and requires greater coverage from the lens.

I didn't realise Sony sensors take 16:9 ratio photos? I thought it was the usual 3:2 like Nikon sensor, since both Nikon and Sony sensor have shared technology (although nikon keeps their magic to themselves (e.g., D3X vs the A900 noise, 2 very different sensors in the end).

Pug · 14 Apr 2010 at 15:17

I think he was referring to the option of 16:9 in the menu. So the crop will work against me? But possibly only wide open, and at say 24mm I'll be ok?

p0ss3s3d · 14 Apr 2010 at 15:20

Well the rings are only about £2.50 so if it only wokrs between 50 and 150mm it doesn't really matter for £2.50.

Pug · 14 Apr 2010 at 15:52

yah, sorta pails into insignificane compared toa £400 lens i guess! The other option is to sell it on, and buy a 60mm, with a step-up for my 55mm lens.

Stupot_ · 14 Apr 2010 at 16:01

Pug said:
The other option is to sell it on, and buy a 60mm, with a step-up for my 55mm lens.

Right I'm getting confused with what you've got...!

thread title said:
55mm filter, 60mm lens

Anyway, after googling it appears that your lens is a 62mm thread which makes more sense. So, either buy a 62mm filter if you don't plan on getting any more lenses, or buy a 77mm filter + step up ring which could be a lot more versatile if you buy more lenses.

Pug · 14 Apr 2010 at 16:15

sorry I've been posting these on my iphone whilst out and about, and probably havent given it the full attention it needed!

You are of course correct, thanks for the info

D.P. · 14 Apr 2010 at 16:46

I would buy a 67mm filter If I knew I would never need anything large (Nikon has mostly settled on 67mm being the alrgest for consumer lenses like 18-85 and 70-300 VR) some step-down rings for other lenses like 50 1.4 etc.

IF you think you might buy a pro lens with 77mm thread (70-200 2.8 etc). then buying a 77mm filter will save money in the long run. For convenience a 67mm and 77mm might make sense but that is of course very expensive.

For sure you can try the 55mm filter but I doubt it will work except under some settings, and even then with some vignetting.

Pug · 14 Apr 2010 at 16:52

yeah, i dont think i'll be buying PRO lenses, and if i do a £70 filter wont sway my purchase decisions

Thanks for the help though, i'll buy an adapter and see - if its not totally crap result, if it is i'll sell all and buy "big enough" and step down. I'm actually consolidating lenses into this single lens (plus a prime i just impulse bought, oh dear) so will actually have fewer lenses once i buy this one.

Tomsk · 14 Apr 2010 at 17:47

D.P. said:
ERRRM, you got it the wrong way round with the sensor coverage. Sicne the crop factor is 1.5X the sensor is larger than Canon sensors and requires greater coverage from the lens.

You are correct. Serves me right trying to post whilst deciphering a PLC at work.