Hello All,

I bought a Sigma 400mm APO Manual Focus Lens earlier this year second hand. I have only used it a couple of times and have not had much look with getting things in sharp focus.

Today when I looked through the lens with a torch I noticed what looks like an internal element having it entire surface covered in what looks like very tiny dots. When looking straight through the lens with it on the camera you don't notice it. But when I shine a torch through it and look at it at a slight angle I can see one of the internal elements covered in very tiny dots.

Does anyone else have this particular lens? If so can you check to see if yours is identical to mine or if mine has a problem???

Best Regards,

Yecora99

Hello, Thanks for such helpfull information, I'm so glad I joined this website.

Frogfish, next time I use the Tamron I will follow your instructions. I had been using it with a standard Tamron adaptall to Pentax K mount(without any electronic contacts) then i found a second hand Pentax mount with a single electronic contact (I'm not sure what that actually does or if it improves anything?) maybe it will i will have to try and see if I find any difference.

DC Weather - I will take a look at your images when I get a spare moment.

Jeallen01 - I will take a look at Amazon and see if the deal still stands and what it will cost.

I have just looked at my Sigma 400mm APO manual focus lens and noticed one of the internal elements looks very strange, it's as if it has lots of dust particles cross it's entire lens??? I will post a separate message and see if anyone can help / advise if that is a fault or not.

Best Regards,

Yecora99

Frogfish, Thanks for your detailed comments and suggestions. I think you are right. I should keep hold of the money until I find the right lens for the task. I've only recently took an interest in Wildlife Photography after spending most of my time doing Buildings and Architecture / Landscape photography. When I bought the Tamron 500mm I started going out taking wildlife images at places like Dunham Massey, Martin Mere and Hollingworth Lake (so mainly Birds, Deer and Rabbits) The only problem I found with the Tamron 500mm mirror lens was trying to get the correct exposure as I was doing everything in manual mode without any metering. so that was a bit hit and miss. I then recently bought the 400mm Sigma APO Manual focus lens and tried using it with a monopod at Clifton Country Park in Salford to take images of the Crested Grebe and none of them are in focus. I don't know whether it is me doing something wrong or not??? So that is why I thought of getting a new lens for wildlife photography. I don't intend on doing nighttime photography (e.g. Owls etc) just general day time photography at the above listed locations.

Thanks for the link, it looks a great lens but unfortunately my top budget only stretches to £450. Since I have just bought a Pentax 16-45mm f4 lens off e-bay for £181 the 55-300 lens looks like the most sensible option at present.

Once again thank you for your help and advice.

Hello and thank you for your suggestions.

I eventually found the following item, which I think he will like and find amusing. link

Dear Forum members, the company I work for are running the office secret santa this year and I have drawn out the name of our Technical Director who I know is a keen Photographer. I need to find something that costs £10 or less to buy for this guy. Luckily for me he does not own a Pentax camera, so he shouldn't be looking on this website.

Do you have any suggestions???

All I can think of is either a Memory Card, Memory Card Case or a lens cleaning cloth.

Any suggestions will be gratefully received.

Best Regards,

Yecora99

Hello thanks for those who responded.

£450 is my top budget so the lens on sale at SRS is out. I have found Mifsuds advertising a used Sigma 170-500 lens at £399. I don't know if that is any good or not???

The reviews I have read about the Pentax 55-300mm lens is very promising indeed and this looks a dead cert. I have checked a few websites and it appears to my amazement that Jessops have it at the cheapest price

As regards creeping up on something now thats another matter.

Best Regards,

Yecora99

Hello again,

I'm looking to obtain a telephoto zoom lens to help aid me with my Nature and Wildlife photography. I have a Pentax K10D and currently use the following Manual Focus lenses Tamron Adaptall 500mm Mirror lens and the Sigma 400mm APO lens. These give reasonable results. Well the Tamron 500mm Mirror lens gives better results than the Sigma APO lens but's that's another discussion.

I'm looking for something in the range of 50- or 70- maybe upto 200mm or upto 300mm. I have read other peoples comments on another thread about the Pentax 55-300mm is this the ideal Pentax lens I should be spending my money on? Or do others suggest another lens that might be of interest to me either New or used???

I'm looking to spend upto or around £450

Best Wishes,

Yecora99