Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-25-2019, 03:43 AM   #1
Forum Member
universalfocus's Avatar

Join Date: May 2014
Photos: Albums
Posts: 76
Looking for advice regarding lens choice.

Hello Pentax community,

Iīm using Pentax cameras since I bought my K-5 seven years ago and I recently (two years ago) switched to a K-1.

Looking at my images after shootings, I got the feeling that the number of keepers (regarding sharpness) I got is pretty low, which is extremely frustrating, if there are some expenses (traveling, payment for location access, etc.) involved. Itīs between 10 and 50 %, and in some cases of portraitshootings it means that some images where everything else (pose, expression, light etc.) is very good the final image cannot be used because the focus point doesnīt fit.

Mostly it is a defocussation instead of a complete lack of focus, however sending in mostly cheap third party lenses together with the camera, to get them aligned seems a bit costly to me. I tried to use the in-camera option on the K-1 to correct back and front focussing, but still get a lot of defocussed images.

I never spent very much money on the lenses (because I couldnīt) and so my most expensive lens today costs 600 Euro and the others are far behind.
Having the K-1 now for a while, Iīd like to upgrade my lens park to a more reliable and more costly lens, but I donīt want to have much hazzle with it and I canīt do such a purchase every year, so I want to be sure to get a tool that can produce images of professional standard and is reliable.

Iīm also using vintage glass and Iīm not a newbie to lightroom and photoshop, so I know whatīs possible with post work image processing. But if the focus isnīt on the eyes thereīs not that much you can do. So fast and reliable autofocus would be a K-O argument for the new lens.

Iīm doing mostly scenery and portrait work and use lenses between 70 and 300 mm most frequently. Iīm searching for a fast focussing relieable lens in this range (prime or zoom doesnīt matter)
cheaper models are preferred, as the budget is an issue, but I put everything up to 2000 Euro into consideration.

Iīm not planning to buy the lens anytime soon, but I want to take a close look at the options available before I make such a big purchase.

My best lens regarding sharpness now is the Tamron 70-200mm F2.8 Di LD Macro

The best one regarding AF performance is the Sigma 70-300mm F4-5.6 DG OS

So what alternatives make sens in the price areas up to 500 Euro, 1000 Euro and 2000 Euro?

Thanks to everybody for reading and recommendations!

You can get an idea of the kind of work I do here.

08-25-2019, 03:59 AM - 3 Likes   #2
Loyal Site Supporter
Loyal Site Supporter
pschlute's Avatar

Join Date: Mar 2007
Location: Surrey, UK
Photos: Gallery
Posts: 4,610
QuoteOriginally posted by universalfocus Quote
I tried to use the in-camera option on the K-1 to correct back and front focussing, but still get a lot of defocussed images
Your problem may be you are not doing this right. Download the chart from here http://www.kscameraclub.org/docs/pdfs/focus_test_chart_edited.pdf

Camera on a tripod. Remote or 2sec timer. Natural (or your working light) conditions. Centre focus point only.

now for the MOST important bit. You need to do 10 test shots where the lens is forced to focus from minimum focus distance. Then 10 more making it focus from infinity. Only then can you assess the accuracy of your AF and make any adjustments. A single test is useless.

Post your test pictures full size and link them here. Dont upload them here they will be too small.

Use the menu item APPLY ONE to save your adjustment and very importantly make sure the camera is left in APPLY ONE when you exit the menu or you wont have any adjustment applied.
08-25-2019, 04:03 AM   #3
Forum Member
universalfocus's Avatar

Join Date: May 2014
Photos: Albums
Posts: 76
Original Poster
QuoteOriginally posted by pschlute Quote
Your problem may be you are not doing this right. Download the chart from here http://www.kscameraclub.org/docs/pdfs/focus_test_chart_edited.pdf

Camera on a tripod. Remote or 2sec timer. Natural (or your working light) conditions. Centre focus point only.

now for the MOST important bit. You need to do 10 test shots where the lens is forced to focus from minimum focus distance. Then 10 more making it focus from infinity. Only then can you assess the accuracy of your AF and make any adjustments. A single test is useless.

Post your test pictures full size and link them here. Dont upload them here they will be too small.

Use the menu item APPLY ONE to save your adjustment and very importantly make sure the camera is left in APPLY ONE when you exit the menu or you wont have any adjustment applied.
Thank you for the tip. Currently I donīt got time for that, but I definately will do an extensive testing of all my lenses prior to a new purchase. Just canīt spend that day at the moment.
08-25-2019, 05:15 AM - 1 Like   #4
Pentaxian
Kozlok's Avatar

Join Date: Jun 2012
Location: Albuquerque
Photos: Gallery
Posts: 2,939
The Tamron is a great lens, and focuses about as well as any fast lens. My guess is the reason you get better keeper rate with the Sigma is because the aperture is slower, giving greater depth of field. Also, never use the Tamron right at 200mm/f2.8. At up to about 175mm, f2.8 is good. At greater than 175mm, don't shoot faster than f4.

Can you post several examples of your "Bad" shots? It will help us gauge just how far off of focus you really are. Post several examples. Are you always back-focused? Half the time back focused, half the time front focused?

Another question, are you using single point focus, or are you using multi-point focus? In my personal experience, I never have luck with multi-point focus. I use single point, and chose whichever point is where I'm going to place the person's eye.

Another thing I do is make sure and refocus several times just in case. I will also sometimes stop down further than my perfect aperture, just to get a greater DOF and get something. If you are shooting only at f2.8, you are going to get much fewer keepers than at f4, and you'll do even better at f5.6. An f5.6 shot well-focused but without dreamy bokeh is better than an f2.8 shot focused in the wrong place.

One final tip, I will setup in burst mode and fire off 10 or so shots quickly, and do that a few times. Usually 1 of the 10 is perfect just due to the very small movements between shots.

If all of this doesn't help, they only way I know to get great focus on the eye every time is to buy a Sony and use their eye autofocus. In the videos I've seen, it looks amazing. That is an expensive, but easy, path to take.


Last edited by Kozlok; 08-25-2019 at 05:24 AM.
08-25-2019, 05:33 AM - 1 Like   #5
Loyal Site Supporter
Loyal Site Supporter
pschlute's Avatar

Join Date: Mar 2007
Location: Surrey, UK
Photos: Gallery
Posts: 4,610
QuoteOriginally posted by universalfocus Quote
Thank you for the tip. Currently I donīt got time for that, but I definately will do an extensive testing of all my lenses prior to a new purchase. Just canīt spend that day at the moment.
If your K1 is like mine it may need a similar adjustment (+ or - ) to counter FF/BF for every lens you own.

Buying a new lens will have the same problem.
08-25-2019, 05:39 AM   #6
Forum Member
universalfocus's Avatar

Join Date: May 2014
Photos: Albums
Posts: 76
Original Poster
QuoteOriginally posted by pschlute Quote
If your K1 is like mine it may need a similar adjustment (+ or - ) to counter FF/BF for every lens you own.

Buying a new lens will have the same problem.
Hm, ok , I thought that more expensive Pentax lenses might be more spot on, because they have better QC and are better optimized for the Pentax cameras.

So I got a lot of adjustment and testing work myself to do then.

---------- Post added 25-08-19 at 15:22 ----------

QuoteOriginally posted by Kozlok Quote
The Tamron is a great lens, and focuses about as well as any fast lens. My guess is the reason you get better keeper rate with the Sigma is because the aperture is slower, giving greater depth of field. Also, never use the Tamron right at 200mm/f2.8. At up to about 175mm, f2.8 is good. At greater than 175mm, don't shoot faster than f4.

Can you post several examples of your "Bad" shots? It will help us gauge just how far off of focus you really are. Post several examples. Are you always back-focused? Half the time back focused, half the time front focused?

Another question, are you using single point focus, or are you using multi-point focus? In my personal experience, I never have luck with multi-point focus. I use single point, and chose whichever point is where I'm going to place the person's eye.

Another thing I do is make sure and refocus several times just in case. I will also sometimes stop down further than my perfect aperture, just to get a greater DOF and get something. If you are shooting only at f2.8, you are going to get much fewer keepers than at f4, and you'll do even better at f5.6. An f5.6 shot well-focused but without dreamy bokeh is better than an f2.8 shot focused in the wrong place.

One final tip, I will setup in burst mode and fire off 10 or so shots quickly, and do that a few times. Usually 1 of the 10 is perfect just due to the very small movements between shots.

If all of this doesn't help, they only way I know to get great focus on the eye every time is to buy a Sony and use their eye autofocus. In the videos I've seen, it looks amazing. That is an expensive, but easy, path to take.
I agree, itīs a wonderful lens. Yes, Iīm using single spot focussing over viewfinder (because focussing over Live View is very slow), sometimes I use middle spot focussing and reframe to speed things up (maybe not a good idea with such shallow DOF).


These are focussed on the ear instead of the eye (ISO 200, 100-140mm, 1/100 (hey we got shake reduction donīt we? )

K1 Tamron 70-200-3 - inrvision's Sta.sh


K1 Tamron 70-200-2 - inrvision's Sta.sh


This one hit, but it was F 2.8 so I just got the lashes but not the iris.

K1 Tamron 70-200-4 - inrvision's Sta.sh


It could also be that just more training with that lens would help, because the slightest movements here can "ruin" the image.


QuoteQuote:
If all of this doesn't help, they only way I know to get great focus on the eye every time is to buy a Sony and use their eye autofocus. In the videos I've seen, it looks amazing. That is an expensive, but easy, path to take
That would be very sad. My only other preferred brand is Fuji.

(Itīs just an emotional thing, I donīt like the Sony designs.)

Last edited by universalfocus; 08-25-2019 at 09:14 AM.
08-25-2019, 07:37 AM - 2 Likes   #7
Loyal Site Supporter
Loyal Site Supporter
pschlute's Avatar

Join Date: Mar 2007
Location: Surrey, UK
Photos: Gallery
Posts: 4,610
QuoteOriginally posted by universalfocus Quote
Hm, ok , I thought that more expensive Pentax lenses might be more spot on, because they have better QC and are better optimized for the Pentax cameras.

So I got a lot of adjustment and testing work myself to do then.
It is all about manufacturing tolerances, both in lenses, and in cameras. We never noticed it in the days of film but with 36MP on a hi res screen we can inspect in great detail and see the flaws. This is why the manufacturers introduced user adjustable AF menu items.

Even a brand new modern DFA lens may be at the extremes of tolerance and require adjustment on every camera.

Or a camera might require the adjustment if the AF sensor is at the extremes of tolerances. My k1 requires between +6/+10 on all my lenses.

Each camera lens combination can be different. It really is worth spending the effort to get the AF/FA correct, then you will really start to see the difference in the field. Right click the picture and select view image, then you can zoom

My K1 and DFA 50mm 1.4 requires +8. Have a look at the detail around the eye when you get the lens/camera calibrated. link here to my Flickr full size image to show the detail. This is at 1.4

08-25-2019, 04:21 PM - 1 Like   #8
Pentaxian




Join Date: Dec 2016
Location: Southeastern Michigan
Posts: 2,993
All you'd need to get your FL close to 300 mm would be a TC with your fine Tamron 70-200mm f/2.8 lens. If it does need AF adjustment, it looks to me like it would not take much.

08-26-2019, 11:17 AM   #9
Forum Member
universalfocus's Avatar

Join Date: May 2014
Photos: Albums
Posts: 76
Original Poster
QuoteOriginally posted by mikesbike Quote
All you'd need to get your FL close to 300 mm would be a TC with your fine Tamron 70-200mm f/2.8 lens. If it does need AF adjustment, it looks to me like it would not take much.
Thanks a lot. I was thinking about a lens upgrade, but if the difference to the Tamron isnīt that big, Iīll try to get the most out of the stuff I already own first.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
advice regarding lens, euro, eye, f2.8, focus, image, images, k-1, k-mount, k1, lens, lenses, pentax, pentax lens, post, purchase, shots, slr lens, sony, tamron, time
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Lens choice advice leecue Pentax SLR Lens Discussion 9 09-24-2017 06:26 PM
Advice requested regarding K-1 rumplestiltskin Pentax K-1 31 08-18-2017 06:30 PM
Need Ethical Advice Regarding Lens Purchase vagabond79 General Talk 26 08-28-2013 05:59 AM
Advice for KX kit lens choice... TOUGEFC Pentax DSLR Discussion 24 05-28-2010 08:14 PM
A little advice regarding account signature settings... alderfall Welcomes and Introductions 4 01-25-2009 01:25 PM



All times are GMT -7. The time now is 06:30 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top