Lens Hood for smc-F 28mm?

**Lowell Goudge** · 07-12-2012, 08:23 AM - **1 Like**

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there is a spreadsheet called Hoodcalc which I uploaded some time ago. this can be used to calculate the maximum round filter that can be used for the lens based upon sensor format

Blue · 07-12-2012, 11:44 AM

Originally posted by Lowell Goudge

there is a spreadsheet called Hoodcalc which I uploaded some time ago. this can be used to calculate the maximum round filter that can be used for the lens based upon sensor format

I wonder if there is a way to get it to work for the SoldBear stepdown ring style of hoods?

**Lowell Goudge** · 07-12-2012, 12:12 PM

BLUE

The calculation uses the actual diameter of the front element , the diameter of the opening, the distance from the opening to the front element (including any set back in the lens from filter threads to front element), and the FOV as a function of sensor format.

as long as the hole is larger than the FOV for the front element diameter, and hole to front element distance, probably. Note here i keep saying front element diameter and not filter thread. I am deliberately being very specific here. My SMC-M 100/4 has a front element diameter of 25mm. so something quite a bit smaller than the 49mm filter thread still will not necessairly impact the FOV

nocturnal · 12-18-2012, 10:25 PM

Originally posted by seventysixersfan

I just have to say that I am so very happy with my new F 28mm attached to my K-X; it feels like a perfect match-- great FOV, compact and light, excellent IQ. It may well get stuck to my camera for a while...

I am waiting for my Pentax-A 28mm f/2.8 to arrive (without a hood) and I am wondering which hood to use.

Did you use a 49mm-28mm step down ring instead of a hood?

I'm finding it difficult to understand how that can work in full aperture, excuse my 'noviceness'

Nocturnal

SOldBear · 12-18-2012, 11:13 PM

Originally posted by nocturnal

Did you use a 49mm-28mm step down ring instead of a hood?

I'm finding it difficult to understand how that can work in full aperture, excuse my 'noviceness'

I'm using 49-28mm stepdown ring for Pentax DFA 100WR Macro, DFA 50 Macro, FA 50 F/1.7.

My F 28mm F/2.8, before sold to Blue, also had a 49-28mm (I think he's still using it that way). So did my Tamron 90mm Macro and Sigma 50mm Macro (both sold).

This is not my idea. I was just inspired by the hood of the Pentax DA 40mm Ltd.

Blue · 12-19-2012, 06:18 PM

Originally posted by SOldBear

I'm using 49-28mm stepdown ring for Pentax DFA 100WR Macro, DFA 50 Macro, FA 50 F/1.7.

My F 28mm F/2.8, before sold to Blue, also had a 49-28mm (I think he's still using it that way). So did my Tamron 90mm Macro and Sigma 50mm Macro (both sold).

This is not my idea. I was just inspired by the hood of the Pentax DA 40mm Ltd.

I still have that F 28/2.8 and that is the hood set up I use on it. It works well and looks good.

SOldBear · 12-19-2012, 07:33 PM

Originally posted by Blue

I still have that F 28/2.8...

My son is still nagging me for selling the lens. He prefers it to the Sigma 30mm F/1.4, and says that the DA 21mm is just too wide at times.

Blue · 12-19-2012, 07:55 PM

Originally posted by SOldBear

My son is still nagging me for selling the lens. He prefers it to the Sigma 30mm F/1.4, and says that the DA 21mm is just too wide at times.

It is an under appreciated lens. It was one of the lenses I took to Haiti with me in October.

seventysixersfan · 12-20-2012, 09:30 AM

Originally posted by nocturnal

Did you use a 49mm-28mm step down ring instead of a hood?

I went with the cheap Adorama rubber hood that works well but it is a bit bulky. I'm very tempted to try the 49mm-28mm step down ring approach. I saw one offered on ebay for $2; not sure if this would work but for the price it might be worth a shot!

49mm to 28mm Step Down Filter Ring Adapter 49 28 | eBay

audiobomber · 12-20-2012, 09:39 AM

Originally posted by seventysixersfan

I went with the cheap Adorama rubber hood that works well but it is a bit bulky. I'm very tempted to try the 49mm-28mm step down ring approach. I saw one offered on ebay for $2; not sure if this would work but for the price it might be worth a shot!

I have a standard 49mm rubber hood on my FA 28mm now and a 49-28 step-down on order. I tried the DA 40mm hood and it vignetted noticeably.

seventysixersfan · 12-20-2012, 09:45 AM

from where did you order your 49-28 step down may I ask?

audiobomber · 12-20-2012, 10:39 AM

Originally posted by seventysixersfan

from where did you order your 49-28 step down may I ask?

EBay Canada, from the same company as shown in your link above.

seventysixersfan · 12-20-2012, 11:00 AM

great, thanks Dan!

audiobomber · 12-20-2012, 11:17 AM

Originally posted by seventysixersfan

great, thanks Dan!

I dont' know how it will work yet, but if it vignettes I intend to file away the corners.

nocturnal · 12-20-2012, 02:19 PM

Originally posted by audiobomber

I dont' know how it will work yet, but if it vignettes I intend to file away the corners.

Did it vignette?

12-18-2012, 10:25 PM	#19
nocturnal Veteran Member Join Date: Dec 2012 Photos: Gallery Posts: 507	49mm-28mm step down ring? Originally posted by seventysixersfan I just have to say that I am so very happy with my new F 28mm attached to my K-X; it feels like a perfect match-- great FOV, compact and light, excellent IQ. It may well get stuck to my camera for a while... I am waiting for my Pentax-A 28mm f/2.8 to arrive (without a hood) and I am wondering which hood to use. Did you use a 49mm-28mm step down ring instead of a hood? I'm finding it difficult to understand how that can work in full aperture, excuse my 'noviceness' Nocturnal

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07-12-2012, 08:23 AM - 1 Like	#16
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,888	Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. there is a spreadsheet called Hoodcalc which I uploaded some time ago. this can be used to calculate the maximum round filter that can be used for the lens based upon sensor format

07-12-2012, 11:44 AM	#17
Blue Moderator Site Supporter Join Date: Jun 2008 Location: Florida Hill Country Photos: Gallery \| Albums Posts: 17,377	Originally posted by Lowell Goudge there is a spreadsheet called Hoodcalc which I uploaded some time ago. this can be used to calculate the maximum round filter that can be used for the lens based upon sensor format I wonder if there is a way to get it to work for the SoldBear stepdown ring style of hoods?

07-12-2012, 12:12 PM	#18
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,888	BLUE The calculation uses the actual diameter of the front element , the diameter of the opening, the distance from the opening to the front element (including any set back in the lens from filter threads to front element), and the FOV as a function of sensor format. as long as the hole is larger than the FOV for the front element diameter, and hole to front element distance, probably. Note here i keep saying front element diameter and not filter thread. I am deliberately being very specific here. My SMC-M 100/4 has a front element diameter of 25mm. so something quite a bit smaller than the 49mm filter thread still will not necessairly impact the FOV

12-18-2012, 11:13 PM	#20
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	Originally posted by nocturnal Did you use a 49mm-28mm step down ring instead of a hood? I'm finding it difficult to understand how that can work in full aperture, excuse my 'noviceness' I'm using 49-28mm stepdown ring for Pentax DFA 100WR Macro, DFA 50 Macro, FA 50 F/1.7. My F 28mm F/2.8, before sold to Blue, also had a 49-28mm (I think he's still using it that way). So did my Tamron 90mm Macro and Sigma 50mm Macro (both sold). This is not my idea. I was just inspired by the hood of the Pentax DA 40mm Ltd.

12-19-2012, 06:18 PM	#21
Blue Moderator Site Supporter Join Date: Jun 2008 Location: Florida Hill Country Photos: Gallery \| Albums Posts: 17,377	Originally posted by SOldBear I'm using 49-28mm stepdown ring for Pentax DFA 100WR Macro, DFA 50 Macro, FA 50 F/1.7. My F 28mm F/2.8, before sold to Blue, also had a 49-28mm (I think he's still using it that way). So did my Tamron 90mm Macro and Sigma 50mm Macro (both sold). This is not my idea. I was just inspired by the hood of the Pentax DA 40mm Ltd. I still have that F 28/2.8 and that is the hood set up I use on it. It works well and looks good.

12-19-2012, 07:33 PM	#22
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	Originally posted by Blue I still have that F 28/2.8... My son is still nagging me for selling the lens. He prefers it to the Sigma 30mm F/1.4, and says that the DA 21mm is just too wide at times.

12-19-2012, 07:55 PM	#23
Blue Moderator Site Supporter Join Date: Jun 2008 Location: Florida Hill Country Photos: Gallery \| Albums Posts: 17,377	Originally posted by SOldBear My son is still nagging me for selling the lens. He prefers it to the Sigma 30mm F/1.4, and says that the DA 21mm is just too wide at times. It is an under appreciated lens. It was one of the lenses I took to Haiti with me in October.

12-20-2012, 09:30 AM	#24
seventysixersfan Pentaxian Join Date: Aug 2010 Location: Alexandria, VA Posts: 2,054 Original Poster	Originally posted by nocturnal Did you use a 49mm-28mm step down ring instead of a hood? I went with the cheap Adorama rubber hood that works well but it is a bit bulky. I'm very tempted to try the 49mm-28mm step down ring approach. I saw one offered on ebay for $2; not sure if this would work but for the price it might be worth a shot! 49mm to 28mm Step Down Filter Ring Adapter 49 28 \| eBay

12-20-2012, 09:39 AM	#25
audiobomber Veteran Member Join Date: May 2008 Location: Sudbury, Ontario Photos: Albums Posts: 6,806	Originally posted by seventysixersfan I went with the cheap Adorama rubber hood that works well but it is a bit bulky. I'm very tempted to try the 49mm-28mm step down ring approach. I saw one offered on ebay for $2; not sure if this would work but for the price it might be worth a shot! I have a standard 49mm rubber hood on my FA 28mm now and a 49-28 step-down on order. I tried the DA 40mm hood and it vignetted noticeably.

12-20-2012, 09:45 AM	#26
seventysixersfan Pentaxian Join Date: Aug 2010 Location: Alexandria, VA Posts: 2,054 Original Poster	from where did you order your 49-28 step down may I ask?

12-20-2012, 10:39 AM	#27
audiobomber Veteran Member Join Date: May 2008 Location: Sudbury, Ontario Photos: Albums Posts: 6,806	Originally posted by seventysixersfan from where did you order your 49-28 step down may I ask? EBay Canada, from the same company as shown in your link above.

12-20-2012, 11:00 AM	#28
seventysixersfan Pentaxian Join Date: Aug 2010 Location: Alexandria, VA Posts: 2,054 Original Poster	great, thanks Dan!

12-20-2012, 11:17 AM	#29
audiobomber Veteran Member Join Date: May 2008 Location: Sudbury, Ontario Photos: Albums Posts: 6,806	Originally posted by seventysixersfan great, thanks Dan! I dont' know how it will work yet, but if it vignettes I intend to file away the corners.

12-20-2012, 02:19 PM	#30
nocturnal Veteran Member Join Date: Dec 2012 Photos: Gallery Posts: 507	Originally posted by audiobomber I dont' know how it will work yet, but if it vignettes I intend to file away the corners. Did it vignette?