Modified DA*60-250/4 on K-1

Started Jul 15, 2016 | Discussions
Greyser Veteran Member • Posts: 6,246
Modified DA*60-250/4 on K-1
14

A few days ago I bumped into this thread:

http://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/304092-da-60-250-mod-ff.html

DA*60-250/4 is one of my favorite lens. I'm not good at street photography, but my best shots in this category are done with this lens.

To make it short. Yesterday I have modified the lens as suggested and took a few shots today to see how it went.

The link above is quite informative. However, I'm putting some picture aid for you. If you need more details, let me know please.

Initial lens condition.

Look at the black ring flange inside K-mount bayonet behind two SDM gold contacts. That is the one causing vignetting to be removed.

Close up of the tube removed.

Remove the SGM contacts first. Then you have to unscrew only three out of four shiny screws on cylindrical side of the bayonet. Only the left screw out of two screws located next to each other shall be removed.

And another veiw from inside

The ring with light obstructive flange scraped out.

Aluminum exposed areas are painted with black Sharpie. Please note that I did not separate the flange from the tube. I kept the whole assembly glued together when removing the flange.

That's how the lens looks now

And finally wide open shot (f/4) at 60mm. No vignetting whatsoever

Strangly there is some slight vignetting at longer end wide open (250mm, f/4).

However, it is easy to remove at PP, and it is usually gone completely at f/5.6.

The bottom line: I may take it easy with D FA 70-200/2.8 for now :-).

Good luck

 Greyser's gear list:Greyser's gear list
Nikon D500 Nikon D850 Sigma 24-105mm F4 DG OS HSM Sigma 500mm F4 Sport Nikon AF-S 70-200mm F2.8E FL ED VR +2 more
Pentax K-1 Pentax K-m (K2000)
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one eyed willy New Member • Posts: 4
Re: Modified DA*60-250/4 on K-1

Thanks for this! What was your method of scraping out the flange...dremel? Did it take long?

OP Greyser Veteran Member • Posts: 6,246
Re: Modified DA*60-250/4 on K-1

one eyed willy wrote:

Thanks for this! What was your method of scraping out the flange...dremel? Did it take long?

For more control and safety I used manual 3-blade scrapper. It took about 30min. to take the flange off.

BTW: if you follow the link posted in OP and go to very end, there is an example of not cutting off the flange and substitute a tube with household item.

 Greyser's gear list:Greyser's gear list
Nikon D500 Nikon D850 Sigma 24-105mm F4 DG OS HSM Sigma 500mm F4 Sport Nikon AF-S 70-200mm F2.8E FL ED VR +2 more
ozdean
ozdean Forum Pro • Posts: 26,127
Re: Modified DA*60-250/4 on K-1

Good job Greyser!

I don't suppose you tried the lens without the whole tube & SDM Contacts?

1 Would the aperture lever still work?

2 Would screw drive operate?

3 Would it solve vignetting at 250 & f4?

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Regards Dean - Capturing Creation
N.B. All my Images are Protected by Copyright

 ozdean's gear list:ozdean's gear list
Pentax MX-1 Pentax K-5 IIs Pentax K-50 Pentax smc DA* 55mm F1.4 SDM Pentax smc DA 15mm F4 ED AL Limited +13 more
OP Greyser Veteran Member • Posts: 6,246
Re: Modified DA*60-250/4 on K-1

ozdean wrote:

Good job Greyser!

I don't suppose you tried the lens without the whole tube & SDM Contacts?

I did not

1 Would the aperture lever still work?

The lever is not affected in any way. So, most likely yes.

2 Would screw drive operate?

I doubt it. You can try to tape the SDM contacts or, in opposite, shorten the contacts with aluminum foil.

3 Would it solve vignetting at 250 & f4?

May be not. Honestly I don't care. I always shoot it stopped down a little.

 Greyser's gear list:Greyser's gear list
Nikon D500 Nikon D850 Sigma 24-105mm F4 DG OS HSM Sigma 500mm F4 Sport Nikon AF-S 70-200mm F2.8E FL ED VR +2 more
one eyed willy New Member • Posts: 4
Re: Modified DA*60-250/4 on K-1
1

Ah I see. I would be most interested in modifying the existing tube as you did, but I am unfamiliar with a "manual 3 blade scraper" tool and google is not much help there as I end up with a range of search results. Would you please link a picture of what this tool looks like so I can make sure to get the right equipment. Thank you.

ozdean
ozdean Forum Pro • Posts: 26,127
Re: Modified DA*60-250/4 on K-1

Yes agree at 250 I would have it 5.6 + and probably f8

The tube and flocking is obviously there to absorb excess light and dare I say the flange for APSc light absorption ie to stop it reflecting around in the mirror box.

-- hide signature --

Regards Dean - Capturing Creation
N.B. All my Images are Protected by Copyright

 ozdean's gear list:ozdean's gear list
Pentax MX-1 Pentax K-5 IIs Pentax K-50 Pentax smc DA* 55mm F1.4 SDM Pentax smc DA 15mm F4 ED AL Limited +13 more
OP Greyser Veteran Member • Posts: 6,246
Re: Modified DA*60-250/4 on K-1

one eyed willy wrote:

Ah I see. I would be most interested in modifying the existing tube as you did, but I am unfamiliar with a "manual 3 blade scraper" tool and google is not much help there as I end up with a range of search results. Would you please link a picture of what this tool looks like so I can make sure to get the right equipment. Thank you.

The official name of the tool is Triangular Blade Scraper or Three Corner Scraper

 Greyser's gear list:Greyser's gear list
Nikon D500 Nikon D850 Sigma 24-105mm F4 DG OS HSM Sigma 500mm F4 Sport Nikon AF-S 70-200mm F2.8E FL ED VR +2 more
one eyed willy New Member • Posts: 4
Re: Modified DA*60-250/4 on K-1

Perfect...now I see what specific tool it is, thanks! All this time I had been thinking that baffle ring was metal, but now knowing you scrapped it off I realize it must not be. Is that correct, is it some kind of plastic or other softernthan metal material?

chris gunn
chris gunn Veteran Member • Posts: 9,307
Re: Modified DA*60-250/4 on K-1

Good for you, and the Pentax community!

Thanks for you work.

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cheers!
Gunn
-- Get a big lens and get closer™.

OP Greyser Veteran Member • Posts: 6,246
Re: Modified DA*60-250/4 on K-1
1

one eyed willy wrote:

Perfect...now I see what specific tool it is, thanks! All this time I had been thinking that baffle ring was metal, but now knowing you scrapped it off I realize it must not be. Is that correct, is it some kind of plastic or other softernthan metal material?

It is aluminum, but thin. I did it in about 30min.

 Greyser's gear list:Greyser's gear list
Nikon D500 Nikon D850 Sigma 24-105mm F4 DG OS HSM Sigma 500mm F4 Sport Nikon AF-S 70-200mm F2.8E FL ED VR +2 more
OP Greyser Veteran Member • Posts: 6,246
Re: Modified DA*60-250/4 on K-1

chris gunn wrote:

Good for you, and the Pentax community!

Not sure about Ricoh-Pentax officials

 Greyser's gear list:Greyser's gear list
Nikon D500 Nikon D850 Sigma 24-105mm F4 DG OS HSM Sigma 500mm F4 Sport Nikon AF-S 70-200mm F2.8E FL ED VR +2 more
one eyed willy New Member • Posts: 4
Re: Modified DA*60-250/4 on K-1

Fantastic, thanks so much fo all the info. Its all perfectly clear now and I can't wait to do the mod as soon as my lens arrives.

klimbkat
klimbkat Senior Member • Posts: 2,452
Re: Modified DA*60-250/4 on K-1

Do you have any idea whether or to what extent this mod will affect APS-C performance (if at all)?  Seems easy enough to do and appears to bring the lens from 92% FF to about 99.5% . . .

DarylK
DarylK Senior Member • Posts: 2,198
Re: Modified DA*60-250/4 on K-1

Thanks for the post.  I find it very tempting to buy this lens as a low cost full frame lens alternative to the new DFA 70-200 (albeit at a sacrifice of one stop).  My old DA*50-135 on APSC worked great for shooting speakers at conferences and I view the 60-250 to do similarly on the K-1.  It's smaller size and weight compared to the 70-200 would make it more convenient for outdoor hiking trips as well.

Daryl

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Great photography is largely a matter of perspective, both visually and mentally - Daryl Kottwitz (but probably said before )
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 DarylK's gear list:DarylK's gear list
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OP Greyser Veteran Member • Posts: 6,246
Re: Modified DA*60-250/4 on K-1

DarylK wrote:

Thanks for the post. I find it very tempting to buy this lens as a low cost full frame lens alternative to the new DFA 70-200 (albeit at a sacrifice of one stop). My old DA*50-135 on APSC worked great for shooting speakers at conferences and I view the 60-250 to do similarly on the K-1. It's smaller size and weight compared to the 70-200 would make it more convenient for outdoor hiking trips as well.

I shot about 200 frames on past weekend with modified lens and K-1. All of them came out sharp and with no vignette at all. However, I was shooting mostly at f/8 and a few shots at f/6.3.

 Greyser's gear list:Greyser's gear list
Nikon D500 Nikon D850 Sigma 24-105mm F4 DG OS HSM Sigma 500mm F4 Sport Nikon AF-S 70-200mm F2.8E FL ED VR +2 more
OP Greyser Veteran Member • Posts: 6,246
Re: Modified DA*60-250/4 on K-1

klimbkat wrote:

Do you have any idea whether or to what extent this mod will affect APS-C performance (if at all)?

APS-C should not be affected at all. If it is important to you, I may try it on coming weekend.

Seems easy enough to do and appears to bring the lens from 92% FF to about 99.5% . . .

Please elaborate on this. I'm not sure what you meant.

 Greyser's gear list:Greyser's gear list
Nikon D500 Nikon D850 Sigma 24-105mm F4 DG OS HSM Sigma 500mm F4 Sport Nikon AF-S 70-200mm F2.8E FL ED VR +2 more
klimbkat
klimbkat Senior Member • Posts: 2,452
Re: Modified DA*60-250/4 on K-1

Greyser wrote:

klimbkat wrote:

Do you have any idea whether or to what extent this mod will affect APS-C performance (if at all)?

APS-C should not be affected at all. If it is important to you, I may try it on coming weekend.

My understanding is that this baffle has some function related to APS-C and I'm curious to know what the impact is, if any, as it may affect both usage options and resale value.

Seems easy enough to do and appears to bring the lens from 92% FF to about 99.5% . . .

Please elaborate on this. I'm not sure what you meant.

Well, I believe you noted some residual vignetting (others have as well) which, while fixable in post, still means not quite 100%.  My own tests indicated that even without the mod, worst case vignetting reduced the usable area by about 8% from true full frame, thus my 92% figure.  I've been using the lens on the K-1 and simply accommodating this by shooting a little wider and then cropping.  For some stuff, say shooting performers in a dark night club, the whole frame is usable since the corners are generally dark anyway.  Assuming I learn of no real downside to the mod, I will definitely do it - the DA* 60-250 is a superb lens and is already great on the K-1.

DarylK
DarylK Senior Member • Posts: 2,198
Re: Modified DA*60-250/4 on K-1

klimbkat wrote:

Greyser wrote:

klimbkat wrote:

Do you have any idea whether or to what extent this mod will affect APS-C performance (if at all)?

APS-C should not be affected at all. If it is important to you, I may try it on coming weekend.

My understanding is that this baffle has some function related to APS-C and I'm curious to know what the impact is, if any, as it may affect both usage options and resale value.

Seems easy enough to do and appears to bring the lens from 92% FF to about 99.5% . . .

Please elaborate on this. I'm not sure what you meant.

Well, I believe you noted some residual vignetting (others have as well) which, while fixable in post, still means not quite 100%. My own tests indicated that even without the mod, worst case vignetting reduced the usable area by about 8% from true full frame, thus my 92% figure. I've been using the lens on the K-1 and simply accommodating this by shooting a little wider and then cropping. For some stuff, say shooting performers in a dark night club, the whole frame is usable since the corners are generally dark anyway. Assuming I learn of no real downside to the mod, I will definitely do it - the DA* 60-250 is a superb lens and is already great on the K-1.

Thanks to the ingenuity and bravery of my fellow Pentaxians here and on the other forum, should I buy this lens, I'll certainly be doing a baffle mod to make it more compatible with my K-1.  However, I will probably limit the modification to filing out corners to accommodate the sensor corners/geometry and leave the rest of the baffle in place.  That way, if there is some kind of subtle benefit to the baffle, most of it will still be there to do it's thing.  I'm mentioning this as food for thought for others thinking of making this modification.

Before I do anything though, I need to sell some gear on the other forum to create some spending money on full frame compatible lenses (the DFA 24-105 and perhaps the DA*60-200 are likely the first buys).  Off topic, I'm looking for super-wide too, but not sure the 15-30 is for me yet.

Daryl

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There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Great photography is largely a matter of perspective, both visually and mentally - Daryl Kottwitz (but probably said before )
My gallery: http://darylkottwitzphoto.smugmug.com
My shots on PPG: http://www.pentaxphotogallery.com/artists/darylkottwitz

 DarylK's gear list:DarylK's gear list
Pentax K-3 Pentax K-1 Pentax smc DA 15mm F4 ED AL Limited Pentax smc DA 10-17mm F3.5-4.5 ED (IF) Fisheye Pentax smc DA 12-24mm F4.0 ED AL (IF) +12 more
OP Greyser Veteran Member • Posts: 6,246
Re: Modified DA*60-250/4 on K-1

klimbkat wrote:

Greyser wrote:

klimbkat wrote:

Do you have any idea whether or to what extent this mod will affect APS-C performance (if at all)?

APS-C should not be affected at all. If it is important to you, I may try it on coming weekend.

My understanding is that this baffle has some function related to APS-C and I'm curious to know what the impact is, if any, as it may affect both usage options and resale value.

The only function I think about is the control of possible reflections that may reach a sensor, keeping them at lowest level posible. Without internal flange/baffle the difference is negligeble I think.

Regarding resale value. I love this lens and I will not sell it, period. However, it depends of potential user what he/she appreciate the most. Pure collectable value of untouched piece of optics or versatility of both APS-C and FF usage.

Seems easy enough to do and appears to bring the lens from 92% FF to about 99.5% . . .

Please elaborate on this. I'm not sure what you meant.

Well, I believe you noted some residual vignetting (others have as well) which, while fixable in post, still means not quite 100%. My own tests indicated that even without the mod, worst case vignetting reduced the usable area by about 8% from true full frame, thus my 92% figure. I've been using the lens on the K-1 and simply accommodating this by shooting a little wider and then cropping. For some stuff, say shooting performers in a dark night club, the whole frame is usable since the corners are generally dark anyway. Assuming I learn of no real downside to the mod, I will definitely do it - the DA* 60-250 is a superb lens and is already great on the K-1.

Ah. These are not a big concerns to me. First of all I rarely shoot wide open. The only long end around 250mm might be affected. And at f/5.6 it is not visible at all. I would be very careful with persantage calculations. It is quite neglegible. And today right in the digital era we mostly crop to frame perfectly

Also even with quite simple recent Photo software all vignetting is very controllable.

 Greyser's gear list:Greyser's gear list
Nikon D500 Nikon D850 Sigma 24-105mm F4 DG OS HSM Sigma 500mm F4 Sport Nikon AF-S 70-200mm F2.8E FL ED VR +2 more
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