Push on Lens Caps.

[Jevon Carey]

Google isn't really being my friend here so I need to ask if anyone can point me in a direction for finding push on type lens caps that don't cost more than the lens itself? 31mm, 39mm, and 42mm required. Thanks in advance.

 

[Petrochemist]

Google isn't really being my friend here so I need to ask if anyone can point me in a direction for finding push on type lens caps that don't cost more than the lens itself? 31mm, 39mm, and 42mm required. Thanks in advance.

I've picked up a few in various sizes from e-bay over the years, I suspect they originally came from binoculars, these days I suspect the easiest option is just to 3D print them.

For applications where strength is not an issue I've also made some modified ones from craft paper. That was the easiest way to end up with aperture control on my monster 150/1.2 projector lens (paper cap with a hole cut that's one stop less than wide open, then paper discs for smaller apertures that can be held on with this cap)
Push on caps don't seem to be made at 5" diameters
A challenging lens by Mike Kanssen, on Flickr

 

[Jevon Carey]

I've picked up a few in various sizes from e-bay over the years, I suspect they originally came from binoculars, these days I suspect the easiest option is just to 3D print them.

For applications where strength is not an issue I've also made some modified ones from craft paper. That was the easiest way to end up with aperture control on my monster 150/1.2 projector lens (paper cap with a hole cut that's one stop less than wide open, then paper discs for smaller apertures that can be held on with this cap)
Push on caps don't seem to be made at 5" diameters
A challenging lens by Mike Kanssen, on Flickr

thank you

 

[AERO]

Google isn't really being my friend here so I need to ask if anyone can point me in a direction for finding push on type lens caps that don't cost more than the lens itself? 31mm, 39mm, and 42mm required. Thanks in advance.

Oddly....ALIEXPRESS AND TEMU advertise them in various sizes..worth a search
e.g.. https://www.aliexpress.com/item/100...false&gad_source=1&gad_campaignid=17190468917

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https://www.temu.com/ul/kuiper/un9.html?subj=goods-un&_bg_fs=1&_p_jump_id=894&_x_vst_scene=adg&goods_id=601104840864432&sku_id=17616723332255&adg_ctx=a-db8355f4~c-15f3decd~f-acf40fc1&_x_ads_sub_channel=shopping&_p_rfs=1&_x_ns_prz_type=-1&_x_ns_sku_id=17616723332255&_x_ns_gid=601104840864432&mrk_rec=1&_x_ads_channel=google&_x_gmc_account=5584549166&_x_login_type=Google&_x_ns_gg_lnk_type=adr&_x_ads_account=8308307013&_x_ads_set=22891346396&_x_ads_id=186862286834&_x_ads_creative_id=769242329516&_x_ns_source=g&_x_ns_gclid=Cj0KCQjwjIPSBhCCARIsABGyK7sYy6PHL-UKoiAYkb-aINIzM4PM-j7SHB1U7i02DtWhOUHLk6SOY1MaAiTvEALw_wcB&_x_ns_placement=&_x_ns_match_type=&_x_ns_ad_position=&_x_ns_product_id=5584549166-17616723332255&_x_ns_target=&_x_ns_devicemodel=&_x_ns_wbraid=CkAKCAjw6f3RBhAYEjAAO-76yzC_XrSUGJH2FAXdaIODBLqda2Sm-PsojztjebkPqOn1WAuf_hr3xVWs5kEaAq2Q&_x_ns_gbraid=0AAAAAo4mICEU1OxjYE0GmMqCARGKK_U2n&_x_ns_targetid=pla-2437237019911&gad_source=1&gad_campaignid=22891346396

 

[Jevon Carey]

Oddly....ALIEXPRESS AND TEMU advertise them in various sizes..worth a search
e.g.. https://www.aliexpress.com/item/100...false&gad_source=1&gad_campaignid=17190468917

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https://www.temu.com/ul/kuiper/un9.html?subj=goods-un&_bg_fs=1&_p_jump_id=894&_x_vst_scene=adg&goods_id=601104840864432&sku_id=17616723332255&adg_ctx=a-db8355f4~c-15f3decd~f-acf40fc1&_x_ads_sub_channel=shopping&_p_rfs=1&_x_ns_prz_type=-1&_x_ns_sku_id=17616723332255&_x_ns_gid=601104840864432&mrk_rec=1&_x_ads_channel=google&_x_gmc_account=5584549166&_x_login_type=Google&_x_ns_gg_lnk_type=adr&_x_ads_account=8308307013&_x_ads_set=22891346396&_x_ads_id=186862286834&_x_ads_creative_id=769242329516&_x_ns_source=g&_x_ns_gclid=Cj0KCQjwjIPSBhCCARIsABGyK7sYy6PHL-UKoiAYkb-aINIzM4PM-j7SHB1U7i02DtWhOUHLk6SOY1MaAiTvEALw_wcB&_x_ns_placement=&_x_ns_match_type=&_x_ns_ad_position=&_x_ns_product_id=5584549166-17616723332255&_x_ns_target=&_x_ns_devicemodel=&_x_ns_wbraid=CkAKCAjw6f3RBhAYEjAAO-76yzC_XrSUGJH2FAXdaIODBLqda2Sm-PsojztjebkPqOn1WAuf_hr3xVWs5kEaAq2Q&_x_ns_gbraid=0AAAAAo4mICEU1OxjYE0GmMqCARGKK_U2n&_x_ns_targetid=pla-2437237019911&gad_source=1&gad_campaignid=22891346396

I will have a look , thank you

 

[Petrochemist]

Oddly....ALIEXPRESS AND TEMU advertise them in various sizes..worth a search

All the front lens caps I saw on either of those links are the normal pinch/clip on type, not what I would class as push on.
All the push on types I have are designed to cover the outside of the lens's filter threads rather than engage in them.

There were a few rear caps as well which I find more useful, but it looks like those are bayonet mount or screw on types. I guess the sizes the OP is after does suggest rear caps, rather than the front caps I assumed originally...

I do have a couple of M42 rear push on caps but only one of them stays on for more than a minute.