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Forum: Pentax DSLR Discussion 05-07-2016, 05:51 AM  
K50 Front focus issue (presumably at lower focal lenghts (under 50mm).
Posted By wbgenetic
Replies: 7
Views: 1,238
2nd test and adjustment:

Tripod.
SR off.
Base Iso.
Target: Matchbox + 2 batteries on each side.
Center focus only.
Shutter delay 2 seconds.
All shots at widest aperture possible.

1. Sigma - with 0 personal and -10 global correction
@ 28mm now perfect at close
@28mm now perfect at distant target (handheld w/ SR).
@105mm now perfect at close
@105 now perfect at distant target (handheld again w/ SR)

2. DA35mm
+3 individual AF added to -10 Global = -7 adjustment
Close target - dead on
Distant target handheld - on target (maybe slightly better with Live view - but could be just me - can't bother again).

3. DA50mm
individual 0, global -10.
Close target - dead on
Distant target - dead on.

There seems to be lots of fluctuation when doing these tests ... previous time at infinity I got certain settings, before this I had completely different settings for the DA50 for example ... now these ... not sure what I will get when I wake up tomorrow ...

Not sure what to make of it...
Forum: Pentax DSLR Discussion 05-07-2016, 03:41 AM  
K50 Front focus issue (presumably at lower focal lenghts (under 50mm).
Posted By wbgenetic
Replies: 7
Views: 1,238
Infinity test + Adjustments.
Setting:
K50
Tripod
Sigma 28-105 2.8-4
DA 35
DA 50

Target is the Billboard in the middle.
Using center focus point only.
Approximately 45 angle degrees from shooting position and 20 meters away.
All open at their widest apertures.
Stabilization off.
Remote shutter with 3 secs delay to prevent hand shutter.
All images resized to 1000px. No PP applied.

Debug menu (global AF adjustment -10).

1. Sigma @ 28mm :
Sigma28LV vs Sigma28PDAF
Adjustment set to 0 (global applied -10).

2. Sigma @ 105mm:
Sigma105LV vs Sigma105PDAF
Adjustment set to 0 (global applied -10).

3. DA 35
DA35LV vs DA35PDAF
Adjustment set to 0 (global applied -10).

4. DA50
DA50LV vs DA50PDAF
Adjustment set to -8 (global applied -10 = effective -18?!)

So problem is that ... these settings are technically all at -10 AF Adjust to start off and in addition this was adjust slightly so that it gives equal focus @ infinity to match the live view ... if I do the same test at a closer range and the same settings - it's bye bye focus again ...
Forum: Pentax DSLR Discussion 05-07-2016, 02:44 AM  
K50 Front focus issue (presumably at lower focal lenghts (under 50mm).
Posted By wbgenetic
Replies: 7
Views: 1,238
Well Live view is spot on for both and they give somewhat sharp results (as much as a super zoom is expected to give)..

I haven't tested the Tamron with a tripod but the Sigma I've tried with a lens alignment test and managed to match the live view result with the pdaf focus using a - 10 adjustment.. Mind you this was at about a meter distance to target..

The DA 35mm is spot on like that, the DA50 also.. The 35mm sometimes gets proper infinity af, the 50mm always..

Could it be a mismatch of lens / body?
Forum: Pentax DSLR Discussion 05-07-2016, 02:09 AM  
K50 Front focus issue (presumably at lower focal lenghts (under 50mm).
Posted By wbgenetic
Replies: 7
Views: 1,238
Hey guys,

running a K50 here and struggling sort of from day one with this ... (sort of).

I started with a manual lens wasn't really an issue here.

Then I had some issues with my 35 2.4 that wouldn't properly focus to infinity at 2.4 (live focus worked just fine). Sent in both to service - but all they seem to have done is dial in -3 in the AF adjustment - it was sort of acceptable so I figured - ok, maybe the lens is sort of soft for this (closer ranges were focusing better).

Then I bought a DA50 and with a -4 AF adjustment I figured at home with some tests it nails the focus pretty much every time.

HOWEVER:
SIGMA 28-105 2.8-4 even when stopped down sort of front focuses. Now at -10 to give some better photos at 5.6.

I recently DID NOT buy a Tamron 18-250 which was in immaculate condition from a fellow ex pentaxian as the focus was always spot on when using 150+ focal lengths - but was terribly front focusing at lower focal lenghts (18 for example gave about 2-3-4 meters of front focus (when trying to focus to infinity)).
We tried setting the AF ADjustment to (debug mode -20) and -10 for the individual setting to try and compensate - alas no success. Still focused perfectly with the long range - but lower focal lengths were eerm ..

Then what came to my mind is - that maybe my camera has problems with front focus at lower focal lenghts in general - ergo the 35mm infinity problem, the SIGMA softish focus and the Tamron huge front focus issue.

Mind you the 50mm is spot on at all settings and distances to focus (tested at 1.8 under artificial and normal light).

I doubt that 3 lenses fail and just 1 works ...

What do you guys think of this?
Forum: Pentax SLR Lens Discussion 05-03-2016, 10:50 AM  
Best sub $100 telephoto lens
Posted By wbgenetic
Replies: 38
Views: 3,371
55-300 for under 100?
Forum: Pentax SLR Lens Discussion 05-03-2016, 09:58 AM  
Best sub $100 telephoto lens
Posted By wbgenetic
Replies: 38
Views: 3,371
What do you guys think of the Tokina 70-210 4-5.6 (or Pentax F 70-210) or the Pentax 50-200 :?
They could fall within that price range if hunted properly ... :?
Forum: Pentax SLR Lens Discussion 05-03-2016, 08:56 AM  
Pentax DA50mm + 52mm Teleconverter :?
Posted By wbgenetic
Replies: 6
Views: 856
How about the:
Tokina SD 70-210mm F4.0-5.6 ?

This instead of the 50 + Tele ...
Forum: Pentax SLR Lens Discussion 05-02-2016, 10:56 AM  
Pentax DA50mm + 52mm Teleconverter :?
Posted By wbgenetic
Replies: 6
Views: 856
Not interested in manual focus lenses for the time being... Got a pile of them also :-D

The sub par 100usd af 100mm + lenses sort of fit...

Maybe a 70-300 Sigma apo dg... But it doesn't seem to be as sharp...
Forum: Pentax SLR Lens Discussion 05-02-2016, 08:58 AM  
Pentax DA50mm + 52mm Teleconverter :?
Posted By wbgenetic
Replies: 6
Views: 856
Not sure where you get dem 100mm for 80bucks... Here i Europe can't seem to find one.

+ the price is still higher but I realize that iq might be better overall..
Forum: Pentax SLR Lens Discussion 05-02-2016, 06:52 AM  
Pentax DA50mm + 52mm Teleconverter :?
Posted By wbgenetic
Replies: 6
Views: 856
Hello guys,

just got a DA 50mm 1.8 lens. I also have a couple of other lenses - but for the sake of traveling light wondered if I could spice things up a bit without a huge drop in IQ.

Has anyone ever tried the front mounted Teleconverters 2x 52mm threaded on their DA 50??

Would be really interested to see which ones produce decent results as if we can pull a 100mm/ F~3.2 it would be rather nice.

Thanks in advance.
Forum: Pentax K-30 & K-50 01-09-2016, 03:06 AM  
My K50 is kaput!!
Posted By wbgenetic
Replies: 44
Views: 7,205
it's not your body but your lens aperture ring stuck...
Forum: Pentax SLR Lens Discussion 01-09-2016, 03:04 AM  
SMC Pentax-M 50mm 1.7 fuzzy/foggy looking pics issue
Posted By wbgenetic
Replies: 8
Views: 1,686
maybe it's foggy outside?

Using the same lens from time to time on k50 no problem.

Also could be too bright... Lower ISO and/or set higher shutter speed.

If it doesn't help could be a bigger issue.


Where did you get the hood for the lens... Looks sick ;-)
Forum: Sold Items 01-01-2016, 03:22 AM  
For Sale - Sold: Pentax K-5IIs, DA WR 18-55, DA 50mm f1.8
Posted By wbgenetic
Replies: 19
Views: 5,166
Hello any chance of shipping outside the US / PayPal registered.
Forum: Video and Pentax HDSLRs 12-31-2015, 11:21 PM  
which Pentax body for video for my daughter?
Posted By wbgenetic
Replies: 157
Views: 11,025
Switch brands... Get an "old" Panasonic lumix g3... Hack it for 100mbps output and you have a great cam + flipping screen.

+ if you so insist you can attach one of your older lenses with an adapter so she can mess with your lenses :-D
Forum: Troubleshooting and Beginner Help 12-20-2015, 10:31 PM  
K-50 and manual lens
Posted By wbgenetic
Replies: 17
Views: 14,039
problem was I had bracketing on. (headbang)

Otherwise the behavior of the camera is normal ;-)

Thanks
Forum: Troubleshooting and Beginner Help 12-20-2015, 12:40 PM  
K-50 and manual lens
Posted By wbgenetic
Replies: 17
Views: 14,039
Hey Guys,

what if I wanted to have full manual control over my camera. Say I set the shutter speed to 1/100 make 3 fast consecutive shots I expect all 3 to have shutter speed of 1/100.

However currently on an M Lens, I get three different speeds using this method.

Any fix for this ?

Thanks.
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