FA* 600 F4 Softness at F4 Issue

**Weevil** · 01-23-2016, 12:43 AM

Hi, I had an option on a FA*600mm f4 lens.... I pulled the trigger on eBay last week because the price was okay, and the seller was in Canada, so no hassle with the customs, or the exchange rate...

I have tested it the first time this week, and I wasn't happy at the results at F4 (to be frank, I did not tested if at smaller apertures... it's the f4 I am interested in. A lens of this class should be sharp wide open IMHO...)

So, I am saying I wasn't happy, because I have the FA*250-600 for a couple years now, and always got pretty sharp images in general, and it would be related to the technique or light condition when I get rejects..

Anyways, I started comparing the two lenses, and I found that indeed , I think there is a problem with this copy of the 600/4...
I checked for any back or front focus issues, and I found that the FA600/4 might have a need for a +4 Back focus adjustment, but anyways, this is not the problem I am seeing, it's the kind of softness, or "haze" I get that bugs me... It seems to me that the lens may be misaligned or have another problem.... I think I would need a CLA....

I am posting some screenshots from my Lightroom, in the hope you would see the same thing as I do...
Most pics are 1:1, and some of the birds are 1:2
The first pics were taken indoor with the flash (Better Beamer, at around 20 meter distance)

I tried to make the shots comparables as much as possible...
The outdoor shots were taken on Thu for the 600/4, and on Fri for the 250-600/5.6, but the Lighting condition were comparable, and about at the same time of the day, and I was at the same spot....
The lenses were always mounted on a sturdy tripod (Gitzo 5541LS), I was also using a Hejnar long lens support kit, mounted an a Benro S8 Video Head... SR was always off on the body of the K3II...
No PP in Lr

https://picasaweb.google.com/114227534831015179379/FA6004VsFA250600?authuser...eat=directlink

Please note that some 600/4 are on the right, and some other on the left in the samples in the link above....

I think that, unfortunately, I want to return that lens because it has a serious softness problem... on the outdoor shots , I took many birds, and none of them were acceptable, whereas, the day after with my FA250-600, I got many very good sharp shots, like this one below cropped 1:3

What do you think... ??

Attached Images

View Picture EXIF

Adam · 01-23-2016, 12:52 AM - **1 Like**

It does look like the lens is front focusing; this is evidenced by the color of the fringing and is especially clear in the stop sign example. Try taking a series of test shots in live view to rule out focusing errors as the cause of the softness.

Also, I would shoot the 600mm at F5.6 and F8 just to have a better sense of your copy's peak performance.

I haven't use the FA* 600mm personally, but based on user reports that I've read over the years, it does seem like moderate softness is to be expected wide-open. Things should look noticeably better by F5.6.

The 250-600mm (which I have used) seems to get better reviews wide-open, but then again it's a whole stop slower.

zapp · 01-23-2016, 12:52 AM

I would use a lens align target and check more than open aperture.
If you are all about f/4, you are correct - the 4/600 will not to the trick. It will be interesting to get opinions on lens variation from other users. Performance at f/4 should be better looking at the images of the face. the color edges/fringes of sharp lines can be an indicator of a lens element misalignment after dropping the lens. Not sure that you want to fix the problem or if it is solvable at all y CLA.

Ceterum censeo: Pentax has not offered large aperture long glass for many years. The used marked is overly expensive and performance is not there after years of use. For one used Pentax 4/600 you will find several from Canon/Nikon glass in two or three vesions in better condition. I do not say, go Canon/Nikon. I am saying that Pentax has a huge gap for people that want/need long tele glass. Call it lighpost lenses - there is none at the moment.

**marcusBMG** · 01-23-2016, 05:51 AM

Borrow a good mirrorless and manual focus using 10X/peaking etc and test again.

Last edited by marcusBMG; 01-23-2016 at 06:09 AM.

elementdtlop · 01-23-2016, 07:06 AM

expecting a lens like that to be super mega sharp wide open seems a little like a reach as far as expectations. id hate to see what you expect in a first date. very narrow dof at that focal length. also youre getting atmospheric interference at that length probably too.

**dadipentak** · 01-23-2016, 07:08 AM

I have a copy of the 600/4 but haven't shot it wide open (and current conditions aren't conducive to testing) but, looking at your samples, there's no contesting your conclusion that your copy is softer than your 250-600 wide open. I think it would be unwise to keep it in hopes that some magician can coax it to deliver the f4 sharpness you were hoping for.

**Weevil** · 01-23-2016, 07:22 AM

Originally posted by marcusBMG

Borrow a good mirrorless and manual focus using 10X/peaking etc and test again.

Can I do that with the k-01 ?
I did try the LV with the K3II and focus peaking.... I did do the tst with the lens aling calibration, and found it was back focusing...
I applied the correction, but not much better

The problem is , in that I havent got any sharp image in the 125 test shots I have done at f4, and even in some I move by error the aperture to 4.5 (9 pics) were not better...

If I cannot use that lens at f4 at all, what's the point to keeping it if my 250-600 already does an awesome job at f5.6 ?

Last edited by Weevil; 01-23-2016 at 07:28 AM.

**Marc Langille** · 01-23-2016, 07:50 AM

My copy of the FA* 250-600/5.6 is stellar wide open.
I've heard some people comment that the 600/4 results can be a tad soft wide open, although several people shooting other brands of older copies of their 600/4 have made that comment too. That seems to be congruent with previous comments made here.

Can always bounce the question to a professional photographer friend who shoots with it regularly - just let me know if you'd like his opinion. Based on your findings so far, it sounds like there's more to it than that. The positive is that you already have the 250-600.

**Weevil** · 01-23-2016, 07:56 AM

Originally posted by Marc Langille

just let me know if you'd like his opinion

Yes please... I also asked @oneill to have a look...

**Marc Langille** · 01-23-2016, 08:09 AM - **1 Like**

Originally posted by Weevil

Yes please... I also asked @oneill to have a look...

Inquiry sent! He's overseas, so it may take a bit of time for a reply.

**marcusBMG** · 01-23-2016, 08:23 AM

Originally posted by Weevil

Can I do that with the k-01 ? I did try the LV with the K3II and focus peaking.... I did do the tst with the lens aling calibration, and found it was back focusing...

Not familiar with the K01. I get best focus accuracy with the evf with my Lumix G1 and NX20. Better than LV on my K5, which I think is pretty similar to the K3 for that... ??
But in any case I agree your pics are soft and it seems like you've already been pretty diligent with your testing.

dane.dawg · 01-23-2016, 08:32 AM

Does the K-3 AF in liveview with this lens?
If so where the photos sharp?

**Weevil** · 01-23-2016, 08:44 AM

Originally posted by dane.dawg

Does the K-3 AF in liveview with this lens?
If so where the photos sharp?

Yes it does, I did that for my tests inside, but no they aren't better

goubejp · 01-23-2016, 09:06 AM

Hi,
I have used this lens during several years; before selling it last year to switch to Nikon.
I sold mine to a canadian member of this forum.
I have written a review of this lens on this forum. Wide open, the lens is a bit soft for sure. Don't forget also that the depth of field is very, very narrow and you need AF tuning.
The lens sweet spot is at f8. More modern lenses reach their optimum less stopped down, but don't forget that it is an old optical design here - back in the 90s
Regards

kulas3VII · 01-23-2016, 09:39 AM

Congratulations to your new investment and good luck,

I owned before that type of lens. It was good. My own opinion F4 was very narrow and a bit of softness and depend on the distance where you shooting from. I contacted Pentax and other repair centers for alignment or focusing but neither Pentax has the answer. I did search on the internet to answer my own questions and make some adjustment (+4) based on my judgement. My opinion, I stop down to F8 thru F11, it depend on the sunlight. If I can get speed of 1/1600 sec or better under ISO 400 have details on the feathers, may be a good day or a lot of keeper. F4 was to hard press for a keeper because of the distance of the subjects. Below are the links of my photos in flickr. Please take a look.. Some of those are focus and some are not. The nearest subject is about 200 ft. and average of 500ft

https://www.flickr.com/gp/crestan/yr69EJ
https://www.flickr.com/gp/crestan/UD82V6

I photograph bald eagles in Conowingo Dam in Maryland and also a contributor in Shutterstock which Bald eagles are my most downloaded images.
I sold my beloved FA* 600 F4 because the body is not fast enough or the lens. In terms of sharpness, it always there. That's the one that I regret a lot. Pentax lens are sharp I mean sharp. Still keeping my landscape lenses. But in terms of fast moving objects, i jump to Canon. keeper rate is very high and very fast both body and lens. Most important aspects of it, i do not missed very important shot..it always there..very fast and accurate.. check the flickr link below.

https://www.flickr.com/gp/crestan/H9274v

Once again, this is my honest opinion of the lens and no offense to anybody. Thanks

01-23-2016, 12:52 AM - 1 Like	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	It does look like the lens is front focusing; this is evidenced by the color of the fringing and is especially clear in the stop sign example. Try taking a series of test shots in live view to rule out focusing errors as the cause of the softness. Also, I would shoot the 600mm at F5.6 and F8 just to have a better sense of your copy's peak performance. I haven't use the FA* 600mm personally, but based on user reports that I've read over the years, it does seem like moderate softness is to be expected wide-open. Things should look noticeably better by F5.6. The 250-600mm (which I have used) seems to get better reviews wide-open, but then again it's a whole stop slower. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

01-23-2016, 12:52 AM	#3
zapp Pentaxian Join Date: Jul 2011 Posts: 2,385	I would use a lens align target and check more than open aperture. If you are all about f/4, you are correct - the 4/600 will not to the trick. It will be interesting to get opinions on lens variation from other users. Performance at f/4 should be better looking at the images of the face. the color edges/fringes of sharp lines can be an indicator of a lens element misalignment after dropping the lens. Not sure that you want to fix the problem or if it is solvable at all y CLA. Ceterum censeo: Pentax has not offered large aperture long glass for many years. The used marked is overly expensive and performance is not there after years of use. For one used Pentax 4/600 you will find several from Canon/Nikon glass in two or three vesions in better condition. I do not say, go Canon/Nikon. I am saying that Pentax has a huge gap for people that want/need long tele glass. Call it lighpost lenses - there is none at the moment. Last edited by zapp; 01-23-2016 at 12:59 AM.

01-23-2016, 07:50 AM	#8
Marc Langille Site Supporter Join Date: Dec 2006 Location: NW Arkansas, USA Posts: 4,710	My copy of the FA* 250-600/5.6 is stellar wide open. I've heard some people comment that the 600/4 results can be a tad soft wide open, although several people shooting other brands of older copies of their 600/4 have made that comment too. That seems to be congruent with previous comments made here. Can always bounce the question to a professional photographer friend who shoots with it regularly - just let me know if you'd like his opinion. Based on your findings so far, it sounds like there's more to it than that. The positive is that you already have the 250-600. Last edited by Marc Langille; 01-23-2016 at 07:59 AM.

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01-23-2016, 05:51 AM	#4
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,869	Borrow a good mirrorless and manual focus using 10X/peaking etc and test again. Last edited by marcusBMG; 01-23-2016 at 06:09 AM.

01-23-2016, 07:06 AM	#5
elementdtlop Forum Member Join Date: Feb 2015 Posts: 97	expecting a lens like that to be super mega sharp wide open seems a little like a reach as far as expectations. id hate to see what you expect in a first date. very narrow dof at that focal length. also youre getting atmospheric interference at that length probably too.

01-23-2016, 07:08 AM	#6
dadipentak Site Supporter Join Date: Jul 2008 Location: Baltimore, Maryland Photos: Gallery Posts: 11,590	I have a copy of the 600/4 but haven't shot it wide open (and current conditions aren't conducive to testing) but, looking at your samples, there's no contesting your conclusion that your copy is softer than your 250-600 wide open. I think it would be unwise to keep it in hopes that some magician can coax it to deliver the f4 sharpness you were hoping for.

01-23-2016, 07:22 AM	#7
Weevil Site Supporter Join Date: May 2012 Location: Near Montréal, Québec Photos: Gallery Posts: 4,445 Original Poster	Originally posted by marcusBMG Borrow a good mirrorless and manual focus using 10X/peaking etc and test again. Can I do that with the k-01 ? I did try the LV with the K3II and focus peaking.... I did do the tst with the lens aling calibration, and found it was back focusing... I applied the correction, but not much better The problem is , in that I havent got any sharp image in the 125 test shots I have done at f4, and even in some I move by error the aperture to 4.5 (9 pics) were not better... If I cannot use that lens at f4 at all, what's the point to keeping it if my 250-600 already does an awesome job at f5.6 ? Last edited by Weevil; 01-23-2016 at 07:28 AM.

01-23-2016, 07:56 AM	#9
Weevil Site Supporter Join Date: May 2012 Location: Near Montréal, Québec Photos: Gallery Posts: 4,445 Original Poster	Originally posted by Marc Langille just let me know if you'd like his opinion Yes please... I also asked @oneill to have a look...

01-23-2016, 08:09 AM - 1 Like	#10
Marc Langille Site Supporter Join Date: Dec 2006 Location: NW Arkansas, USA Posts: 4,710	Originally posted by Weevil Yes please... I also asked @oneill to have a look... Inquiry sent! He's overseas, so it may take a bit of time for a reply.

01-23-2016, 08:23 AM	#11
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,869	Originally posted by Weevil Can I do that with the k-01 ? I did try the LV with the K3II and focus peaking.... I did do the tst with the lens aling calibration, and found it was back focusing... Not familiar with the K01. I get best focus accuracy with the evf with my Lumix G1 and NX20. Better than LV on my K5, which I think is pretty similar to the K3 for that... ?? But in any case I agree your pics are soft and it seems like you've already been pretty diligent with your testing.

01-23-2016, 08:32 AM	#12
dane.dawg Veteran Member Join Date: Aug 2011 Location: B.C. Photos: Gallery Posts: 1,436	Does the K-3 AF in liveview with this lens? If so where the photos sharp?

01-23-2016, 08:44 AM	#13
Weevil Site Supporter Join Date: May 2012 Location: Near Montréal, Québec Photos: Gallery Posts: 4,445 Original Poster	Originally posted by dane.dawg Does the K-3 AF in liveview with this lens? If so where the photos sharp? Yes it does, I did that for my tests inside, but no they aren't better

01-23-2016, 09:06 AM	#14
goubejp Veteran Member Join Date: Oct 2007 Location: France Photos: Albums Posts: 804	Hi, I have used this lens during several years; before selling it last year to switch to Nikon. I sold mine to a canadian member of this forum. I have written a review of this lens on this forum. Wide open, the lens is a bit soft for sure. Don't forget also that the depth of field is very, very narrow and you need AF tuning. The lens sweet spot is at f8. More modern lenses reach their optimum less stopped down, but don't forget that it is an old optical design here - back in the 90s Regards

01-23-2016, 09:39 AM	#15
kulas3VII Veteran Member Join Date: Jun 2008 Location: Somerville, NJ USA Photos: Gallery Posts: 354	Congratulations to your new investment and good luck, I owned before that type of lens. It was good. My own opinion F4 was very narrow and a bit of softness and depend on the distance where you shooting from. I contacted Pentax and other repair centers for alignment or focusing but neither Pentax has the answer. I did search on the internet to answer my own questions and make some adjustment (+4) based on my judgement. My opinion, I stop down to F8 thru F11, it depend on the sunlight. If I can get speed of 1/1600 sec or better under ISO 400 have details on the feathers, may be a good day or a lot of keeper. F4 was to hard press for a keeper because of the distance of the subjects. Below are the links of my photos in flickr. Please take a look.. Some of those are focus and some are not. The nearest subject is about 200 ft. and average of 500ft https://www.flickr.com/gp/crestan/yr69EJ https://www.flickr.com/gp/crestan/UD82V6 I photograph bald eagles in Conowingo Dam in Maryland and also a contributor in Shutterstock which Bald eagles are my most downloaded images. I sold my beloved FA* 600 F4 because the body is not fast enough or the lens. In terms of sharpness, it always there. That's the one that I regret a lot. Pentax lens are sharp I mean sharp. Still keeping my landscape lenses. But in terms of fast moving objects, i jump to Canon. keeper rate is very high and very fast both body and lens. Most important aspects of it, i do not missed very important shot..it always there..very fast and accurate.. check the flickr link below. https://www.flickr.com/gp/crestan/H9274v Once again, this is my honest opinion of the lens and no offense to anybody. Thanks