Search results for 'sensor cleaning' - page 158
Cleaning lenses/filters
If I didn't fit filters to my good lady's lenses they'd always be back at Pentax having the front element replaced, how she manages to chip and scratch them is beyond my ken.....
Posted by andy_bell on 02/05/2014 - 11:06
Cleaning lenses/filters
I just thought it was ironic that I should fit the filter so that I would not have to clean the front element and then after about a year when I take off the filter I find that the front element has become filthy despite this. I do not know how. Trapped dirty air or condensation but it means that ...
Posted by kiwao on 02/05/2014 - 13:48
Cleaning lenses/filters
It's bizarre - the pics from my Sigma 70-300 look no different with or without the uv filter :D My Pentax m200mm f4 hates filters full stop My kit lenses are ok either way My Sigma 50mm macro works well with uv or polarisers and my Vivitar 28mm loves the polariser and cokin 'a's :lol: I ...
Posted by Stuey on 02/05/2014 - 22:30
Cleaning lenses/filters
It's been mentioned a few times that the DA 55-300 hates filters (I agree with this) yet certain other lenses don't seem affected. Does anyone know why this would be? Regards David
Posted by davidstorm on 02/05/2014 - 23:32
Cleaning lenses/filters
I have never read that some lenses did not work well with filters. I have heard that some filters are easier to clean than others. In the video link I posted earlier I think he is a bit heavy handed but maybe that is because I am too careful. This video has good info about cleaning lenses but so...
Posted by kiwao on 03/05/2014 - 05:29
Cleaning lenses/filters
breath and a bit of bog roll, but it's a erate occourance . No filters on my lenses either
Posted by Smeggypants on 03/05/2014 - 06:34
Cleaning lenses/filters
I very rarely need to clean a lens, but always use a lens cap in the bag and lens hood when in use. Cleaning is simple. Use a microfiber lens cleaning cloth, well washed and clean. Flick any dust off, breath lightly on the lens and when the moisture has evaporated wipe carefully with the cloth. ...
Posted by johnriley on 03/05/2014 - 07:59
Cleaning lenses/filters
breath and a bit of bog roll, but it's a erate occourance . No filters on my lenses either How does the breath work? Does it make the bog roll softer and therefore basics bog roll can be used as opposed to super soft triple ply Andrex bog roll?
Posted by kiwao on 03/05/2014 - 08:37
Lens sharpness
Everyone seems to be obsessed with tack sharp images these days and lens MTF resolution figures. So while on this bandwagon why is that the Pentax lenses and other lenses in Pentax mount often (not always) score lower for sharpness than the Nikon equivalents. A prime example of this is the Sigma...
Posted by mikedefieslife on 12/05/2014 - 21:36
Which lenses for Astrophotography?
Hi - DSS does not avoid the star trails, it aligns multiple exposures of the same region of sky. It's the Pentax O-GPS1 that is used when taking the photos that avoids the trails. The Pentax O-GPS1 is a GPS and Astrotracking device that can be used with certain models of Pentax DSLR. If you're no...
Posted by LennyBloke on 24/07/2014 - 09:46
Lens calibration shop
^yup. Whilst lenses do have plenty of adjustment for centration and position of the internal elements, this is to do with setting the length and centration of the intermediate images. It will however affect overall sharpness and bokeh (this is the variance we see within batches). It should no...
Posted by dpm on 29/05/2014 - 06:53
Lens calibration shop
I've always wonder how lenses are calibrated. I've taken some apart to fix them and there doesn't appear to be any adjustments to alignment of lenses. It's all in software* - they just rewrite the look-up tables :) You can of course physically adjust the AF module ( with s screw underneath the bott...
Posted by Smeggypants on 29/05/2014 - 07:25
Lens calibration shop
Press shutter half-way. Move in until you get a beep and CiF lit. Re compose. Shoot. :mrgreen: If you look at the video you will see that there is a CiF range just like a DOF range. I set mine up with an adjustment value so that as I move in on a bug the shutter trips at the beginning of t...
Posted by Algernon on 30/05/2014 - 12:06
Extension Tube
With any lens 1:1 macro will always be 2X the focal length sensor to lens and also 2X the focal length subject to lens. It will always lose 2 stops. (Factor of 4). 1:2 would need 1.5X FL and lose just over a stop (Factor of 2.25). The PDF manuals for Pentax tubes should give the info. for...
Posted by Algernon on 02/06/2014 - 14:10
Extension Tube
Yes, sorry. Of course the exposure changes - if you magnify the same subject area over more pixels on the sensor, the light coming off the subject is spread over more pixels, so the exposure per pixel is less. Sorry for the confusion, posted too quickly there. However, the tubes don't affect ...
Posted by ChrisA on 02/06/2014 - 14:45
Ephotozine review of the 60-250mm
There is a difference but at the normal ISO's that I shoot at, it's just not significcant enough for me to justify a body costing three times that of a K3... Logically the 35mm format D800 sensor is 2.33 times larger than the APS C so not far off three times. The 645Z is only 1.7 times larger than 3...
Posted by K10D on 05/09/2014 - 16:01
Ephotozine review of the 60-250mm
There is a difference but at the normal ISO's that I shoot at, it's just not significcant enough for me to justify a body costing three times that of a K3... Logically the 35mm format D800 sensor is 2.33 times larger than the APS C so not far off three times. The 645Z is only 1.7 times larger than 3...
Posted by jules on 06/09/2014 - 20:52
Ephotozine review of the 60-250mm
Yep! Which is why, if ever do need more image quality I'll be buying a 645z and not a D800 derivative... Moving from a K3 to a 645Z based on Calumet prices is a 7.5 times increase in price based on body only prices. I intend to buy a 645Z based on 645 lenses I already own. I don't know anyone who ca...
Posted by K10D on 07/09/2014 - 01:23
Ephotozine review of the 60-250mm
Yep! Which is why, if ever do need more image quality I'll be buying a 645z and not a D800 derivative... Moving from a K3 to a 645Z based on Calumet prices is a 7.5 times increase in price based on body only prices. I intend to buy a 645Z based on 645 lenses I already own. I don't know anyone who ca...
Posted by jules on 07/09/2014 - 05:15
Tair 3a 300mm f/4.5 soviet rocket launcher shoots bus stops
I picked up a Tair 3A 300mm f/4.5 M42 lens a month or so back, based largely upon its reputation and the previous owners assurances about its condition. The 3A is the more normal looking and focussing version of this lens, not the Photosniper variant. It has a built-in tripod mount with both 1/4 a...
Posted by andrewk on 20/06/2014 - 14:23
